Metals, Non-Metals and Reactivity Series – NDA Chemistry PYQs

Q1. Which one of the following metals occurs in nature in free state?
(a) Gold (b) Sodium (c) Aluminium (d) Copper

Answer: (a) Gold
Gold is the most noble (least reactive) common metal — it never combines with other elements naturally. Sodium and Aluminium are highly reactive — found only in compounds. Gold’s position at the bottom of the reactivity series explains why it is always found pure.
[NDA 2006-II]

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Q2. At 30°C, which three metals are all liquids?
(a) Hg, Fe, Zn (b) Hg, Sn, Pb (c) Zn, Pb, Sn (d) Hg, Ga, Cs

Answer: (d) Hg, Ga, Cs
Mercury (mp = −39°C), Gallium (mp = ~30°C), and Caesium (mp = 28.5°C) are all liquid at 30°C. Iron, Zinc, Tin, and Lead all have much higher melting points.
[NDA 2007-I]

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Q3. Which one among the following elements is polyatomic?
(a) Phosphorus (b) Sulphur (c) Chlorine (d) Aluminium

Answer: (b) Sulphur
Sulphur exists as S₈ — 8 atoms per molecule — making it polyatomic. Phosphorus is P₄ (tetraatomic). Chlorine is Cl₂ (diatomic). Aluminium is a metal — monoatomic.
[NDA 2024-II]

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Q4. Oxygen on reaction with non-metals forms oxides which are:
(a) Basic oxides (b) Acidic oxides (c) Amphoteric oxides (d) Neutral oxides

Answer: (b) Acidic oxides
Non-metal oxides (SO₂, CO₂, NO₂, P₂O₅) dissolve in water to form acids or react with bases to form salts. Metal oxides are basic. ZnO and Al₂O₃ are amphoteric. CO is neutral.
[NDA 2013-II]

Q5. Which one of the following oxides is a neutral oxide?
(a) CO (b) CO₂ (c) Na₂O (d) MgO

Answer: (a) CO
Carbon monoxide does not react with water, acids, or bases — it is neutral. CO₂ forms carbonic acid (acidic). Na₂O forms NaOH (basic). MgO forms Mg(OH)₂ (basic).
[NDA 2025-I]

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Q6. The presence of sulphur in gunpowder:
(a) Decreases the ignition temperature (b) Increases final temperature
(c) Increases explosiveness (d) Makes the powder smokeless

Answer: (a) Decreases the ignition temperature
Sulphur lowers the temperature at which the gunpowder mixture catches fire — making it easier to ignite. Gunpowder = KNO₃ + charcoal + sulphur.
[NDA 2013-II]

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Q7. Statement I: Zinc is used for galvanisation to protect iron from rusting.
Statement II: Zinc is more reactive towards oxygen than iron.
(a) Both true, II correctly explains I (b) Both true, II does not explain I
(c) I true, II false (d) I false, II true

Answer: (a) Both true, Statement II correctly explains Statement I
Zinc is higher in the reactivity series than iron. It corrodes preferentially when both are exposed to moisture and air. As long as any zinc remains, the iron beneath is protected. Zinc’s greater reactivity is exactly why it works.
[NDA 2013-II]

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Q8. To protect steel and iron from rusting, a thin layer of which one of the following metals is applied?
(a) Magnesium (b) Zinc (c) Aluminium (d) Lead

Answer: (b) Zinc
Galvanisation applies zinc on iron/steel. Zinc is more reactive than iron — it acts as a sacrificial anode and corrodes preferentially, protecting the iron beneath.
[NDA 2021-II]

Q9. Cinnabar is an ore of which one of the following?
(a) Copper (b) Zinc (c) Mercury (d) Manganese

Answer: (c) Mercury
Cinnabar = HgS (mercury sulphide). It is the primary ore from which mercury is extracted. Copper pyrites = copper. Zinc blende = zinc.
[NDA 2021-II]

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Q10. Which one of the following represents the correct order of electron releasing tendency of metals?
(a) Zn > Cu > Ag (b) Ag > Cu > Zn (c) Cu > Zn > Ag (d) Cu > Ag > Zn

Answer: (a) Zn > Cu > Ag
In the reactivity series Zn is above Cu, which is above Ag. More reactive = greater tendency to release electrons. Correct decreasing order: Zn > Cu > Ag.
[NDA 2019-II]

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Q11. Which one of the following alkali metals has lowest melting point?
(a) Sodium (b) Potassium (c) Rubidium (d) Caesium

Answer: (d) Caesium
In alkali metals, melting point decreases down the group: Li > Na > K > Rb > Cs. Caesium has the lowest melting point (~28.5°C). Lithium has the highest.
[NDA 2018-I]

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Q12. Which one of the following metals is alloyed with sodium to transfer heat in a nuclear reactor?
(a) Potassium (b) Calcium (c) Magnesium (d) Strontium

Answer: (a) Potassium
Sodium-potassium alloy (NaK) stays liquid over a wide temperature range and conducts heat very efficiently — used as coolant in some nuclear reactors.
[NDA 2018-I]

Q13. Which one of the following elements will NOT react with dilute HCl to produce H₂?
(a) Hg (b) Al (c) Mg (d) Fe

Answer: (a) Hg
Mercury is below hydrogen in the reactivity series — it cannot displace hydrogen from dilute acids. Al, Mg, and Fe are all above hydrogen and react with HCl to produce H₂.
[NDA 2016-I]

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Q14. Which of the following is/are amphoteric?
(a) Al(OH)₃ and Fe(OH)₃ (b) Al(OH)₃ and HCO₃⁻
(c) Ba(OH)₂ and NaOH (d) Al(OH)₃ only

Answer: (b) Al(OH)₃ and HCO₃⁻
Al(OH)₃ reacts with both HCl and NaOH — amphoteric. HCO₃⁻ can donate or accept a proton — also amphoteric. Fe(OH)₃ is only basic. Ba(OH)₂ and NaOH are purely basic.
[NDA 2014-I]

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Q15. Which of the following metals are present in haemoglobin and chlorophyll respectively?
(a) Fe and Mg (b) Fe and Zn (c) Mg and Zn (d) Zn and Mg

Answer: (a) Fe and Mg
Haemoglobin contains Iron at the centre of the heme group — carries oxygen in blood. Chlorophyll contains Magnesium at the centre of the porphyrin ring — captures light for photosynthesis.
[NDA tested via CDS]

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Q16. Which one among the following metals is more reactive than hydrogen?
(a) Mercury (b) Copper (c) Silver (d) Tin

Answer: (d) Tin
Reactivity series: … Fe > Sn (Tin) > Pb > H > Cu > Hg > Ag > Au. Tin is above hydrogen — more reactive. Mercury, Copper, and Silver are below hydrogen.
[NDA 2010-I]

Q19. The correct order of metals in decreasing order of reactivity is:
(a) Iron, Sodium, Silver, Copper (b) Silver, Copper, Iron, Sodium
(c) Sodium, Copper, Silver, Iron (d) Sodium, Iron, Copper, Silver

Answer: (d) Sodium, Iron, Copper, Silver
From the reactivity series: Na (very reactive) > Fe (moderate) > Cu (low) > Ag (least among these). Correct decreasing order = Na > Fe > Cu > Ag.
[NDA 2023-I]

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Q20. An iron nail dipped in copper sulphate solution turns brown. This is due to which type of reaction?
(a) Addition reaction (b) Decomposition reaction
(c) Substitution reaction (d) Displacement reaction

Answer: (d) Displacement reaction
Iron is more reactive than copper. Fe displaces Cu from CuSO₄ solution — iron goes into solution as Fe²⁺, copper deposits on the nail as brown copper metal. Fe + CuSO₄ → FeSO₄ + Cu.
[NDA 2023-I]