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Metals and Non-metals: Class 10 Science Practice Questions

30 original exam-pattern questions with full answers, matched to the current CBSE Class 10 paper design, including case-based questions. Attempt each question before opening the answer — or start a free 14-day trial ↓ for the full bank.

Q1Case-based4 marks

Riya is helping her mother in the kitchen. She notices that the steel spoons and iron tawa remain shiny even after months of use, but the iron nail left outside in the garden has turned reddish-brown and rough. She also sees that her mother uses aluminium foil to wrap food, and it stays clean even after several uses.

Riya is helping her mother in the kitchen. She notices that the steel spoons and iron tawa remain shiny even after months of use, but the iron nail left outside in the garden has turned reddish-brown and rough. She also sees that her mother uses aluminium foil to wrap food, and it stays clean even after several uses.

Read the above situation carefully and answer the following questions:

(a) Name the reddish-brown substance formed on the iron nail. Write its chemical formula.

(b) Name the two conditions that are necessary for the formation of this reddish-brown substance.

(c) Aluminium is a highly reactive metal, yet the aluminium foil does not corrode in air. Give reason. Also, suggest any two methods that can be used to prevent the rusting of iron.

Show answer
(a) The reddish-brown substance formed on the iron nail is rust.
Chemical formula: Fe₂O₃·xH₂O (hydrated iron(III) oxide)
[1 mark]

(b) The two conditions necessary for the formation of rust (corrosion of iron) are:
(i) Presence of oxygen (air)
(ii) Presence of moisture (water)
[1 mark — both conditions required for full mark]

(c) Reason for aluminium not corroding:
Although aluminium is a highly reactive metal, when it is exposed to air, it immediately reacts with oxygen to form a thin, tough layer of aluminium oxide (Al₂O₃) on its surface. This oxide layer is stable and strongly adherent — it prevents further reaction of the underlying aluminium with oxygen or moisture. Therefore, aluminium foil appears to resist corrosion even though aluminium is reactive.
[1 mark]

Two methods to prevent rusting of iron:
(i) Galvanisation — coating the iron surface with a layer of zinc. Zinc is more reactive than iron; it reacts with oxygen preferentially and protects the iron underneath.
(ii) Painting / oiling / greasing — applying paint, oil, or grease on the iron surface creates a barrier that prevents oxygen and moisture from coming into contact with the iron.
(Any other valid method: electroplating, alloying with chromium to make stainless steel — also accepted)
[1 mark — any two correct methods with brief explanation, ½ mark each]
Q2Case-based4 marks

Priya is helping her grandmother sort out old utensils in the kitchen. She finds the following items:

• A shiny copper vessel that has turned greenish on the outside
• An iron tawa (griddle) with reddish-brown patches
• A silver spoon that has become dull and dark
• A gold ring that still looks as bright as the day it was bought

Priya is helping her grandmother sort out old utensils in the kitchen. She finds the following items:

• A shiny copper vessel that has turned greenish on the outside
• An iron tawa (griddle) with reddish-brown patches
• A silver spoon that has become dull and dark
• A gold ring that still looks as bright as the day it was bought

Using your knowledge of metals and their properties, answer the following questions:

(a) Name the phenomenon responsible for the reddish-brown patches on the iron tawa. [1]
(b) Why does the gold ring show no change in appearance even after years of use? [1]
(c) Priya's teacher tells her that two conditions are essential for iron to develop reddish-brown patches. Name both conditions. Also explain ONE method Priya's grandmother could use to prevent the iron tawa from developing these patches in future. [2]

Show answer
(a) The reddish-brown patches on the iron tawa are caused by corrosion (rusting).
[1 mark]

(b) Gold is the least reactive metal — it is placed at the very bottom of the reactivity series. It does not react with oxygen, moisture, or any common substance in the environment. Therefore, the gold ring does not corrode or tarnish and retains its shine even after years of use.
[1 mark]

(c) The two conditions essential for iron to rust are:
(i) Presence of oxygen (air)
(ii) Presence of moisture (water)
Both conditions must be present simultaneously — iron does not rust in dry air alone or in oxygen-free water alone.

Prevention method (any ONE acceptable):
Painting: Priya's grandmother can apply a coat of paint on the surface of the iron tawa. The paint layer acts as a barrier between iron and the environment, preventing both oxygen and moisture from coming into contact with the iron surface. This stops the corrosion reaction from occurring.
[2 marks — 1 mark for both conditions correctly named; 1 mark for method with explanation]
Q3Case-based4 marks

Rahul is a Class 10 student doing a Science project on metals. He visits a local blacksmith's workshop and notices several things:
(i) The blacksmith hammers hot iron into different shapes — flat sheets, curved hooks, and thin rods — without the iron cracking or breaking.
(ii) On a shelf, Rahul spots a bottle labelled 'sodium metal — stored under kerosene'. He asks the blacksmith why sodium cannot simply be kept in open air like iron.
(iii) Rahul also notices that some old iron tools in the corner are covered with a reddish-brown layer, while a copper vessel nearby has developed a greenish coating.
(iv) The blacksmith mentions that the iron tools are made harder and more resistant to rust by mixing iron with carbon and chromium to form an alloy called stainless steel.

Read the following passage and answer the questions that follow:

Rahul is a Class 10 student doing a Science project on metals. He visits a local blacksmith's workshop and notices several things:

(i) The blacksmith hammers hot iron into different shapes — flat sheets, curved hooks, and thin rods — without the iron cracking or breaking.
(ii) On a shelf, Rahul spots a bottle labelled 'sodium metal — stored under kerosene'. He asks the blacksmith why sodium cannot simply be kept in open air like iron.
(iii) Rahul also notices that some old iron tools in the corner are covered with a reddish-brown layer, while a copper vessel nearby has developed a greenish coating.
(iv) The blacksmith mentions that the iron tools are made harder and more resistant to rust by mixing iron with carbon and chromium to form an alloy called stainless steel.

Based on the above passage, answer the following questions:

(a) Name the physical property of iron that allows the blacksmith to hammer it into different shapes without it cracking. [1 mark]

(b) Why is sodium metal stored under kerosene? Write the chemical equation for the reaction that would occur if sodium were exposed to air (reaction with oxygen). [1 mark]

(c) (i) Name the reddish-brown substance formed on iron tools and state the two conditions necessary for it to form.
(ii) Name the greenish coating on the copper vessel. [2 marks]

OR

(c) What is an alloy? State any two advantages of making stainless steel over using pure iron. [2 marks]

Show answer
(a) Malleability.
Iron is malleable — it can be beaten into thin sheets or any shape without cracking or breaking. This is a characteristic physical property of metals. [1 mark]

(b) Sodium is stored under kerosene because it is highly reactive. If exposed to air, it reacts vigorously with atmospheric oxygen and moisture, and may even catch fire. Storing it under kerosene prevents contact with air and water.

Chemical equation for reaction of sodium with oxygen:
4Na + O₂ → 2Na₂O
(Sodium oxide is formed.) [1 mark]

(c) (i) The reddish-brown substance formed on iron tools is rust (iron(III) oxide / Fe₂O₃·xH₂O), chemically known as hydrated iron oxide.

Two conditions necessary for rusting of iron:
• Presence of oxygen (air)
• Presence of moisture (water / water vapour)
Both conditions must be present simultaneously for rusting to occur.

(ii) The greenish coating on the copper vessel is basic copper carbonate (a mixture of copper carbonate and copper hydroxide: CuCO₃·Cu(OH)₂), commonly called patina or verdigris. It forms when copper reacts slowly with CO₂, moisture, and oxygen present in the air. [2 marks]

OR

(c) An alloy is a homogeneous mixture of two or more metals, or a metal and a non-metal, prepared to obtain a material with improved or specific desired properties. (Example: stainless steel = iron + carbon + chromium.)

Two advantages of stainless steel over pure iron:
(i) Stainless steel is harder and stronger than pure iron, making it more durable and suitable for cutting tools, surgical instruments, and cookware.
(ii) Stainless steel is highly resistant to corrosion (rusting), unlike pure iron which rusts easily in the presence of oxygen and moisture. This makes it much longer-lasting. [2 marks]
Q4Case-based4 marks

A science teacher showed her class three metals — sodium (Na), iron (Fe), and copper (Cu) — and asked students to predict what would happen when each is placed in cold water. Riya said: 'Sodium will react violently, iron will not react, and copper will not react.' Her teacher confirmed she was correct.

A science teacher showed her class three metals — sodium (Na), iron (Fe), and copper (Cu) — and asked students to predict what would happen when each is placed in cold water. Riya said: 'Sodium will react violently, iron will not react, and copper will not react.' Her teacher confirmed she was correct.

Based on this scenario, answer the following:

(a) Name the products formed when sodium reacts with cold water. Write the balanced chemical equation for this reaction.

(b) Why does iron NOT react with cold water, even though it is a metal?

(c) Riya's teacher then asked: 'Which of these three metals would you use to store in kerosene oil, and why? Also, if iron is exposed to steam instead of cold water, what products are formed?' Answer both parts.

Show answer
(a) When sodium reacts with cold water, the products formed are sodium hydroxide (NaOH) and hydrogen gas (H₂).

Balanced chemical equation:
2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂↑

[1 mark: correct products named; 1 mark: balanced equation with state symbols and ↑]

(b) Iron does not react with cold water because it is a moderately reactive metal and is positioned below sodium and calcium in the reactivity series. Its reactivity is not high enough to break the bonds in water molecules at room temperature. Iron requires the high temperature of steam to react.
[1 mark]

(c) Sodium should be stored in kerosene oil. This is because sodium is an extremely reactive metal — it reacts vigorously with both oxygen in air and with moisture/water present in air. Kerosene oil acts as a protective layer that prevents sodium from coming into contact with air and water, thus avoiding a dangerous reaction.

When iron is exposed to steam (instead of cold water), the products formed are iron(II,III) oxide (Fe₃O₄) and hydrogen gas (H₂).

Balanced equation:
3Fe(s) + 4H₂O(g) →[Steam / Heat]→ Fe₃O₄(s) + 4H₂↑
[1 mark: sodium stored in kerosene with correct reason; ½ mark: Fe₃O₄ and H₂ named as products; ½ mark: balanced equation]
Q5Case-based4 marks

A chemistry teacher set up four test tubes for her students. Each test tube contained a dilute acid — hydrochloric acid (HCl) in tubes 1 and 2, and sodium hydroxide solution (NaOH) in tubes 3 and 4. She then added the following substances: powdered magnesium oxide (MgO) to tube 1, powdered aluminium oxide (Al₂O₃) to tube 2, powdered aluminium oxide (Al₂O₃) to tube 3, and powdered magnesium oxide (MgO) to tube 4. After shaking, students recorded whether the oxide dissolved (reacted) or remained undissolved. The teacher explained that how an oxide behaves depends on its chemical nature, and that this property has important practical applications in everyday life and industry.

Read the following passage carefully and answer the questions that follow:

A chemistry teacher set up four test tubes for her students. Each test tube contained a dilute acid — hydrochloric acid (HCl) in tubes 1 and 2, and sodium hydroxide solution (NaOH) in tubes 3 and 4. She then added the following substances: powdered magnesium oxide (MgO) to tube 1, powdered aluminium oxide (Al₂O₃) to tube 2, powdered aluminium oxide (Al₂O₃) to tube 3, and powdered magnesium oxide (MgO) to tube 4. After shaking, students recorded whether the oxide dissolved (reacted) or remained undissolved. The teacher explained that how an oxide behaves depends on its chemical nature, and that this property has important practical applications in everyday life and industry.

(a) What type of oxide is Al₂O₃? Name ONE other oxide that shows the same behaviour.
(b) Predict the observation in test tube 4. Give a reason for your answer.
(c) Write balanced chemical equations for the reactions that occur in test tubes 2 and 3.

Show answer
(a) Al₂O₃ is an amphoteric oxide — a metallic oxide that reacts with both acids and bases. [½ mark]
Another oxide showing the same behaviour: ZnO (zinc oxide). [½ mark]

(b) Observation in test tube 4: MgO remains undissolved (no reaction occurs) in NaOH solution. [½ mark]
Reason: MgO is a basic oxide. Basic oxides react with acids to form salt and water, but they do NOT react with bases (alkalis). Since tube 4 contains NaOH (a base), MgO does not dissolve. [½ mark]

(c) Reaction in test tube 2 — Al₂O₃ with HCl (acid):
Al₂O₃ + 6HCl → 2AlCl₃ + 3H₂O [1 mark]
(aluminium chloride and water are formed)

Reaction in test tube 3 — Al₂O₃ with NaOH (base):
Al₂O₃ + 2NaOH → 2NaAlO₂ + H₂O [1 mark]
(sodium aluminate and water are formed)

Both reactions confirm that Al₂O₃ is amphoteric — it acts as a base when reacting with an acid (tube 2) and as an acid when reacting with a base (tube 3).
Q6Case-based4 marks

A science teacher showed her students the following observations during a lab session:

• A shiny grey metal (Metal P) was placed in cold water. It floated, melted, and moved around the surface vigorously, producing a colourless gas that caught fire.
• A dull black solid (Substance Q) was connected in a simple circuit with a battery and a bulb. The bulb lit up.
• A pale yellow solid (Substance R) was hit with a hammer. It crumbled into a powder.
• Metal P was then cut with a knife — it cut easily, like butter.

A science teacher showed her students the following observations during a lab session:

• A shiny grey metal (Metal P) was placed in cold water. It floated, melted, and moved around the surface vigorously, producing a colourless gas that caught fire.
• A dull black solid (Substance Q) was connected in a simple circuit with a battery and a bulb. The bulb lit up.
• A pale yellow solid (Substance R) was hit with a hammer. It crumbled into a powder.
• Metal P was then cut with a knife — it cut easily, like butter.

Based on the observations, answer the following questions:

(a) Identify Metal P. Name the colourless gas produced when Metal P reacted with water. [1 mark]

(b) What type of substance is Q — metal or non-metal? Justify your answer based on the observation. [1 mark]

(c) (i) Write the balanced chemical equation for the reaction of Metal P with water, naming all products. [1 mark]
(ii) State ONE reason why Substance R is a non-metal, and give ONE other property of non-metals in general. [1 mark]

Show answer
(a) Metal P is Sodium (Na).
The colourless gas produced is hydrogen (H₂). [1 mark]

(b) Substance Q is a non-metal.
Justification: Non-metals generally do not conduct electricity. However, graphite (a form of carbon, a non-metal) is an exception — it conducts electricity because it has one free electron per carbon atom that can move between layers. The observation (bulb lighting up) shows Q conducts electricity; since it is described as a dull black solid (characteristic of graphite), it is a non-metal that is an exception to the general rule. [1 mark]

*(Examiner note: Award 1 mark if student correctly identifies Q as graphite/non-metal and states that graphite is an exception among non-metals that conducts electricity. Accept any correct justification linking the dull appearance and conductivity to graphite.)*

(c)(i) Balanced chemical equation for sodium reacting with water:

2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂↑

Products: Sodium hydroxide (NaOH) and hydrogen gas (H₂). [1 mark]

(c)(ii)
— Substance R is a non-metal because it is brittle — it crumbles when hit with a hammer instead of being beaten into sheets. Non-metals are non-malleable (brittle).
— One other general property of non-metals: Non-metals are poor conductors of heat and electricity (except graphite). [1 mark]
Q7Case-based4 marks

Riya is a metallurgy student given three unlabelled ore samples: Sample A (carbonate ore of zinc — ZnCO₃, calamine), Sample B (sulphide ore of copper — Cu₂S, chalcocite), and Sample C (oxide ore of aluminium — Al₂O₃, bauxite). She must apply the correct pre-treatment and extraction steps for each metal.

A metallurgy student, Riya, is working in a laboratory and is given three unlabelled ore samples — Sample A (a carbonate ore of zinc), Sample B (a sulphide ore of copper), and Sample C (an oxide ore of aluminium). She needs to extract each metal using the correct sequence of metallurgical steps.

(a) Identify the correct pre-treatment process Riya should use for Sample A before reduction, and write the balanced chemical equation for it.

(b) Identify the correct pre-treatment process Riya should use for Sample B before reduction, and write the balanced chemical equation for it.

(c) Riya attempts to reduce the ore of aluminium (Sample C) using carbon (coke) at high temperature, but finds it does not work. Explain why carbon cannot reduce aluminium oxide. State the method actually used to extract aluminium and write the reaction at the cathode during this process.

Show answer
(a) Sample A is ZnCO₃ (zinc carbonate / calamine), a carbonate ore. The correct pre-treatment is Calcination — heating strongly in the absence or limited supply of air. This converts the carbonate ore to the metal oxide, which can then be reduced.

Balanced equation:
ZnCO₃ →(Heat / Calcination)→ ZnO + CO₂↑
[1 mark: correct process name + correct balanced equation]

(b) Sample B is Cu₂S (copper sulphide / chalcocite), a sulphide ore. The correct pre-treatment is Roasting — heating strongly in excess air (oxygen). This converts the sulphide ore to the metal oxide and releases sulphur dioxide gas.

Balanced equation:
Cu₂S + O₂ →(Heat / Roasting / excess air)→ 2Cu + SO₂↑
OR (if Cu₂O is given as intermediate step, also acceptable):
2Cu₂S + 3O₂ →(Heat)→ 2Cu₂O + 2SO₂↑
[1 mark: correct process name + correct balanced equation]

(c) Aluminium is a highly reactive metal — it lies above carbon in the reactivity series. A more reactive element cannot be displaced by a less reactive one. Since aluminium is more reactive than carbon, carbon cannot reduce Al₂O₃ — aluminium would require more energy to be displaced than carbon can provide. Therefore, reduction by coke fails for aluminium.

Method actually used: Electrolysis of molten aluminium oxide (Al₂O₃) — this process is called electrolytic reduction. (Bauxite is first purified, then mixed with cryolite to lower its melting point, and then electrolysed in a carbon-lined steel tank.)

Reaction at the cathode during electrolysis:
Al³⁺ + 3e⁻ → Al
(Aluminium ions gain electrons at the cathode and are deposited as molten aluminium metal.)
[1 mark: correct explanation of why carbon fails (reactivity series reasoning) + 1 mark: correct method (electrolysis) + cathode reaction]
Q8Case-based4 marks

Rohit is helping his grandmother clean some old utensils in the kitchen. He notices that the iron tawa has developed a reddish-brown coating, the copper vessel has a greenish layer on it, and the aluminium pressure cooker looks dull but has no coloured deposit. His grandmother tells him that they store water in a silver pot, which has remained shiny for years. Rohit is curious about why different metals behave differently when exposed to air and moisture.

Rohit is helping his grandmother clean some old utensils in the kitchen. He notices that the iron tawa has developed a reddish-brown coating, the copper vessel has a greenish layer on it, and the aluminium pressure cooker looks dull but has no coloured deposit. His grandmother tells him that they store water in a silver pot, which has remained shiny for years. Rohit is curious about why different metals behave differently when exposed to air and moisture.

Based on the above passage, answer the following questions:

(a) Name the phenomenon responsible for the reddish-brown coating on the iron tawa. Write its chemical formula. [1 mark]

(b) Rohit observes that the silver pot remains shiny for a very long time. Which property of silver is responsible for this? Where does silver appear in the reactivity series relative to iron? [1 mark]

(c) Rohit wants to protect the iron tawa from further rusting. Suggest ANY TWO methods he can use to prevent rusting, giving one reason for each. [2 marks]

Show answer
(a) The phenomenon responsible for the reddish-brown coating on the iron tawa is Rusting (Corrosion of iron).

The reddish-brown deposit is hydrated iron(III) oxide, with the chemical formula: Fe₂O₃·xH₂O

[Award ½ mark for naming rusting/corrosion; ½ mark for correct formula Fe₂O₃·xH₂O or Fe₂O₃]

(b) Silver is a very low-reactivity metal. It does not react readily with oxygen or moisture in the air. Therefore, it does not corrode or tarnish easily and remains shiny for a long time.

In the reactivity series, silver (Ag) appears well below iron (Fe). Iron is more reactive than silver.

[Award ½ mark for stating low reactivity / does not react with air and moisture; ½ mark for correctly stating silver is below iron in the reactivity series]

(c) Any TWO of the following methods with reason:

(i) Painting: Painting the surface of the iron tawa creates a barrier that prevents oxygen and moisture from coming into contact with the iron surface, stopping the rusting reaction.

(ii) Galvanising: Coating the iron with a layer of zinc (galvanisation) protects it because zinc is more reactive than iron. Even if the zinc layer is scratched, zinc continues to react preferentially, protecting the iron underneath.

(iii) Oiling or Greasing: Applying oil or grease on the iron surface creates a protective layer that keeps oxygen and moisture away from the metal surface, thus preventing rusting.

(iv) Alloying: Converting iron into an alloy such as stainless steel (by mixing with chromium and nickel) makes it resistant to rusting because the alloy does not react with oxygen and moisture as readily as pure iron.

[Award 1 mark for each correct method with a valid reason — ½ mark for method name + ½ mark for reason. Any two correct methods with reasons = 2 marks]
Q9MCQ1 mark

Which of the following physical properties is generally associated with non-metals but NOT with metals?

Show answer
Option (A) is correct.

Explanation: Non-metals in the solid state are generally brittle — they crumble or shatter when subjected to mechanical stress, because they lack the metallic bonding that allows layers of atoms to slide over one another. Metals, by contrast, are malleable (can be beaten into thin sheets) and ductile (can be drawn into wires), making brittleness exclusively a non-metal characteristic among the given options. High thermal conductivity and lustre (shiny appearance) are properties of metals, not non-metals, and malleability is also a defining property of metals. Therefore, brittleness in solid state is the property associated with non-metals but not with metals.
Q10MCQ1 mark

Which one of the following statements about the physical properties of metals and non-metals is NOT true?

Show answer
Option (D) is correct.

Explanation: As a general rule, non-metals are poor conductors of heat and electricity. However, graphite — an allotrope of carbon, which is a non-metal — is a good conductor of electricity because each carbon atom in graphite has one free electron that can move between its layers. Since graphite is a well-established exception, the claim that ALL non-metals are poor conductors "without any exception" is not true. Options (A), (B), and (C) are all correct statements: metals are sonorous, non-metals are brittle and non-malleable, and iodine is a non-metal that displays metallic lustre — a recognised exception to the general non-lustre property of non-metals.
Q11MCQ1 mark

When a metal reacts with dilute sulphuric acid, hydrogen gas is evolved. However, when the same metal reacts with dilute nitric acid, hydrogen gas is NOT evolved. Which of the following correctly explains why hydrogen gas is not produced when a metal reacts with dilute nitric acid?

Show answer
Option (A) is correct.

Explanation: Nitric acid is a strong oxidising agent and oxidises the hydrogen gas produced back to water. When a metal reacts with dilute sulphuric acid, the hydrogen ions are reduced to H₂ gas which escapes freely. However, when the same metal reacts with dilute HNO₃, any hydrogen produced is immediately oxidised by HNO₃ to form water, so no H₂ gas is evolved. Instead, oxides of nitrogen such as NO (with dilute HNO₃) or NO₂ (with concentrated HNO₃) are released as the reduction products of nitric acid.
Q12MCQ1 mark

Which of the following sets of elements share the common characteristic of being neither purely metallic nor purely non-metallic, often called metalloids or semi-metals?

Show answer
Option (A) is correct.

Explanation: Elements that exhibit properties intermediate between metals and non-metals are called metalloids or semi-metals. They possess some metallic characteristics (such as a lustrous appearance) and some non-metallic characteristics (such as brittleness), and their electrical conductivity lies between that of conductors and insulators, making them semiconductors. Silicon (Si), Germanium (Ge), and Arsenic (As) are classic examples of such metalloids. In contrast, Sodium, Magnesium, and Aluminium are all metals; Sulphur, Phosphorus, and Chlorine are all non-metals; and Iron, Copper, and Zinc are all metals — none of these sets contains elements with intermediate character.
Q13MCQ1 mark

A student observes that certain metal oxides react with hydrochloric acid to form salt and water, while the same oxides also react with sodium hydroxide solution to form salt and water. Which of the following lists correctly identifies ALL such oxides from the options given below?

I. CaO
II. ZnO
III. Al₂O₃
IV. Na₂O

Show answer
Option (B) is correct.

Explanation: Metal oxides that react with both acids and bases to form salt and water are called amphoteric oxides. ZnO reacts with HCl to form ZnCl₂ + H₂O and with NaOH to form Na₂ZnO₂ + H₂O; Al₂O₃ reacts with HCl to form AlCl₃ + H₂O and with NaOH to form NaAlO₂ + H₂O. CaO and Na₂O are basic oxides — they react with acids but do not react with NaOH solution to form salt and water. Therefore, only ZnO (II) and Al₂O₃ (III) are amphoteric oxides.
Q14MCQ1 mark

A metal M is malleable, ductile, and conducts electricity. When M is placed in dilute hydrochloric acid, hydrogen gas is evolved. Which of the following best describes the nature of the oxide formed by M?

Show answer
Option (A) is correct.

Explanation: The properties described — malleability, ductility, electrical conductivity, and reaction with dilute hydrochloric acid to evolve hydrogen gas — are all characteristic properties of a metal. Metals react with oxygen to form metal oxides, and these oxides are basic in nature because they react with acids to form salt and water (e.g., CuO + 2HCl → CuCl₂ + H₂O) and dissolve in water to form alkaline solutions (e.g., Na₂O + H₂O → 2NaOH). Since metal M displaces hydrogen from dilute HCl, it is a typical reactive metal and not an amphoteric metal like zinc or aluminium, so its oxide is purely basic, not amphoteric.
Q15MCQ1 mark

Iron, magnesium, copper, and aluminium are all classified as metals. Which of the following correctly identifies a property that is common to ALL of these elements?

Show answer
Option (A) is correct.

Explanation: Lustre, malleability, and good conduction of heat and electricity are general physical properties shared by all metals. Iron, magnesium, copper, and aluminium all exhibit these properties. Option (B) is incorrect because only highly reactive metals such as potassium, sodium, and calcium react vigorously with cold water; iron does not react with cold water at all, and copper does not react with water under any ordinary condition. Option (C) is incorrect because amphoteric oxides are formed only by aluminium (Al₂O₃) among the four listed metals; iron oxide and copper oxide are basic oxides, not amphoteric. Option (D) is incorrect because diamond is the hardest natural substance, and no metal is harder than diamond; moreover, mercury, a metal, is liquid at room temperature, disproving any claim of universally very high melting points for metals.
Q16MCQ1 mark

The property by virtue of which a metal can be beaten into thin sheets without breaking is called:

Show answer
Option (A) is correct.

Explanation: Malleability is the property of a metal by virtue of which it can be beaten into thin sheets without breaking. Ductility refers to the ability of a metal to be drawn into thin wires, sonority is the property by which a metal produces a ringing sound when struck, and conductivity is the ability to conduct heat or electricity. Since the question specifically describes beating into thin sheets, the property is malleability.
Q17MCQ1 mark

Iron railings left exposed to moist air for a prolonged period develop a reddish-brown coating on their surface. Which of the following statements correctly describes this phenomenon and the chemical composition of the reddish-brown substance formed?

Show answer
Option (A) is correct.

Explanation: When iron is exposed to moist air, it reacts with atmospheric oxygen in the presence of water to undergo corrosion (rusting), a slow oxidation process. The reddish-brown product formed is rust, which is chemically hydrated iron(III) oxide, Fe₂O₃·xH₂O. Galvanisation is a *prevention* method (coating iron with zinc), not a corrosion process, and does not produce iron carbonate; tarnishing refers to surface discolouration in metals such as silver by sulphur compounds, not iron in moist air; electroplating is an electrolytic deposition process and produces no iron chloride coating on railings.
Q18MCQ1 mark

Which of the following metals is present in nature ONLY in its combined state (i.e., it is never found in free/native state) because it is highly reactive?

Show answer
Option (C) is correct.

Explanation: Highly reactive metals react readily with oxygen, water, and other substances in nature, so they exist only in combined form (as ores or compounds) and are never found in the free or native state. Calcium is a highly reactive alkaline earth metal — it reacts vigorously with water and oxygen — and is therefore always found in nature as compounds such as CaCO₃ (limestone) and CaSO₄ (gypsum), never as a free element. Gold and platinum are the least reactive metals (noble metals) and are found in nature in their free/native state. Silver, though moderately reactive, is also sometimes found in native state. Among the given options, only calcium is never found in free state owing to its high reactivity.
Q19MCQ1 mark

A non-metal element 'P', when treated with concentrated nitric acid, forms an oxoacid 'Q'. The same element 'P', when heated in excess oxygen, forms an acidic oxide that dissolves in water to give the same acid 'Q'. Element 'P' and acid 'Q' respectively are:

Show answer
Option (A) is correct.

Explanation: Sulphur is a non-metal that, when oxidised by concentrated nitric acid, is converted to sulphuric acid (H₂SO₄) — the oxoacid Q. When the same element sulphur is heated in excess oxygen, it first forms sulphur dioxide (SO₂), which on further oxidation yields sulphur trioxide (SO₃); this acidic oxide dissolves in water according to SO₃ + H₂O → H₂SO₄, producing the same acid Q. Both pathways thus converge on H₂SO₄, confirming that element P is sulphur and acid Q is sulphuric acid. Options (B), (C), and (D) are incorrect because carbon burned in excess oxygen gives CO₂ which forms carbonic acid (H₂CO₃), phosphorus oxidation gives P₂O₅ forming phosphoric acid (H₃PO₄), and nitrogen with concentrated HNO₃ does not follow this pattern — none of these yield the same acid through both routes described.
Q20MCQ1 mark

A metal M is malleable, ductile, and a good conductor of electricity. When M is heated in air, it forms a basic oxide. When M reacts with dilute hydrochloric acid, hydrogen gas is evolved. Identify the type of substance M belongs to.

Show answer
Option (A) is correct.

Explanation: Metals are characterised by malleability, ductility, and good electrical conductivity. Chemically, metals react with oxygen to form basic oxides and react with dilute acids such as HCl to evolve hydrogen gas. All properties described for M — malleable, ductile, good conductor, basic oxide formation on heating in air, and evolution of H₂ with dilute HCl — are consistent with metallic character. Non-metals are brittle, poor conductors, and form acidic or neutral oxides. Metalloids show only intermediate properties and do not fit all the given criteria. Noble gases are chemically inert and do not react with dilute HCl. Therefore, substance M is a metal.
Q21MCQ1 mark

Which one of the following statements about the physical properties of metals and non-metals is NOT correct?

Show answer
Option (C) is correct.

Explanation: The statement claims that *all* metals are lustrous solids and *all* non-metals are dull and non-lustrous — both parts of this absolute claim are incorrect. Iodine is a non-metal that has a characteristic metallic lustre (shiny purple-black solid), directly contradicting the claim about non-metals. Mercury is a metal that is liquid at room temperature, contradicting the claim that all metals are lustrous solids. Options (A), (B), and (D) are generally correct statements: metals are good conductors, are malleable and ductile, and are sonorous, while non-metals are generally poor conductors and brittle — these hold true with well-known exceptions that are not contradicted by those options.
Q22MCQ1 mark

Phosphorus ignites spontaneously in air and must be stored under water, while sulphur burns in oxygen to form a pungent gas. Both phosphorus and sulphur are classified as non-metals. Which of the following properties is common to BOTH of these elements?

Show answer
Option (A) is correct.

Explanation: Non-metals are characteristically brittle solids (or gases) — they lack malleability and ductility. When non-metals burn in oxygen, they form acidic oxides: phosphorus burns to form P₂O₅, which dissolves in water to give phosphoric acid, and sulphur burns to form SO₂, which dissolves in water to give sulphurous acid — both products are acidic in nature. Options (B) and (C) describe properties of metals (malleable, good conductors of heat and electricity), and Option (D) is also a property of metals, as non-metals do not react with dilute HCl to produce hydrogen gas.
Q23MCQ1 mark

A dentist uses a silver-coloured metallic mixture to fill cavities in teeth. This mixture is prepared by dissolving silver, tin, and copper in mercury. Such a type of mixture of metals is called an amalgam. Which of the following statements correctly identifies an amalgam?

Show answer
Option (A) is correct.

Explanation: An amalgam is a special type of alloy in which mercury (Hg) is one of the constituent metals; other metals such as silver, tin, or copper dissolve in mercury to form this mixture. Option (B) describes brass, which is an alloy of copper and zinc, not mercury. Option (C) describes steel, an alloy of iron and carbon. Option (D) describes solder, an alloy of lead and tin used for joining metal joints. Since the dental filling described in the question is prepared by dissolving silver, tin, and copper in mercury, it is correctly identified as an amalgam — an alloy containing mercury as one of its constituents.
Q24MCQ1 mark

Iron forms an oxide when heated in air. This oxide reacts with dilute hydrochloric acid to form a salt and water. Based on this, which of the following correctly describes the nature of iron oxide?

Show answer
Option (A) is correct.

Explanation: A basic oxide is one that reacts with an acid to form salt and water. Iron oxide (Fe₂O₃) is formed when iron is heated in air; when it reacts with dilute hydrochloric acid, it produces iron chloride (a salt) and water — which is precisely the defining property of a basic oxide. Option (B) is incorrect because being formed by reaction with oxygen does not make an oxide acidic; acidic oxides are typically formed by non-metals and react with bases, not acids. Option (C) is incorrect because iron oxide does not react with bases under normal conditions and therefore cannot be classified as amphoteric. Option (D) is incorrect because a neutral oxide neither reacts with acids nor with bases to form salt and water, which is not the case here.
Q25MCQ1 mark

Silver jewellery gradually loses its shine and develops a black coating when exposed to air containing traces of hydrogen sulphide. Which of the following correctly identifies the black substance formed on the surface of silver and the process responsible for it?

Show answer
Option (A) is correct.

Explanation: Silver reacts with hydrogen sulphide (H₂S) present in air to form silver sulphide (Ag₂S), a black-coloured compound — this process is called tarnishing. The reaction is: 4Ag + 2H₂S + O₂ → 2Ag₂S + 2H₂O. Option (B) is incorrect because rusting is specific to iron, not silver. Option (C) is incorrect because Ag₂CO₃ is pale yellow, not black, and carbon dioxide is not responsible for this reaction. Option (D) is incorrect because galvanisation refers to coating iron with zinc to prevent corrosion, and AgCl is not formed in this process.
Q26MCQ1 mark

Tin cans used for storing food items are made by coating tin over iron. If the tin coating gets scratched and the inner iron surface is exposed to moist air, which of the following correctly describes what happens and why?

Show answer
Option (A) is correct.

Explanation: In the reactivity series, iron is more reactive than tin, meaning iron has a greater tendency to lose electrons (undergo oxidation) in the presence of moisture and oxygen. Tin provides only a physical barrier to iron; unlike zinc in galvanisation, tin does not act as a sacrificial anode. Once the tin coating is scratched and the iron surface is exposed to moist air, iron preferentially loses electrons and undergoes rapid corrosion, forming hydrated iron(III) oxide (Fe₂O₃·xH₂O) — the reddish-brown rust — while the less reactive tin remains unaffected at the scratch.
Q27MCQ1 mark

Which of the following pairs of oxides both react with dilute hydrochloric acid but do NOT react with aqueous sodium hydroxide solution?

Show answer
Option (B) is correct.

Explanation: Oxides that react with dilute hydrochloric acid but do NOT react with aqueous sodium hydroxide are basic oxides. CaO and MgO are both basic oxides — they react with dilute HCl to form a salt and water (CaO + 2HCl → CaCl₂ + H₂O; MgO + 2HCl → MgCl₂ + H₂O) but do not react with NaOH solution. ZnO and Al₂O₃ in Option (A) are amphoteric oxides that react with both acids and bases, so they are eliminated. In Option (D), Al₂O₃ is amphoteric and reacts with NaOH, making that pair incorrect. In Option (C), ZnO is amphoteric and also reacts with NaOH. Only CaO and MgO are purely basic oxides satisfying both conditions.
Q28Short Answer1 mark

Name the method used to extract metals that are highly reactive, such as sodium and potassium.

Show answer
Electrolysis (of their molten ores/compounds) is used to extract highly reactive metals such as sodium and potassium.

These metals cannot be extracted by reduction with carbon because they are more reactive than carbon and would not be displaced by it.
Q29MCQ1 mark

Which one of the following is a chemical property of metals?

Show answer
Option (C) is correct.

Explanation: A chemical property describes how a substance undergoes a chemical change or reaction. When metals react with dilute acids, they displace hydrogen from the acid to form a salt and hydrogen gas — this is a chemical reaction and therefore a chemical property. The remaining options — malleability, ductility, high melting point, and electrical conductivity — are all physical properties, as they describe the physical state or behaviour of the metal without involving any change in its chemical composition.
Q30MCQ1 mark

A blacksmith adds a small amount of carbon to molten iron to produce a harder and stronger material used in construction of bridges and railway tracks. Which of the following correctly identifies the composition of this alloy?

Show answer
Option (A) is correct.

Explanation: An alloy is a homogeneous mixture of two or more metals, or a metal and a non-metal. When a small amount of carbon is added to molten iron, the resulting alloy is steel (carbon steel), which is harder and stronger than pure iron due to the distortion of the regular arrangement of iron atoms by carbon atoms. Steel is widely used in the construction of bridges and railway tracks for this reason. Option (B) is incorrect because iron and zinc gives galvanised iron, which is used for corrosion prevention, not as a structural alloy of this type. Options (C) and (D) are incorrect as iron–tin and iron–copper are not standard construction alloys formed by this process.

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