SSC CGL 2024 Tier-I · 12 September 2024, Shift 2 · General Awareness · Question 19 of 100

Text as printed on a candidate's response sheet for this shift; answer per SSC's tentative key as marked on that sheet. Solution last reviewed 6 September 2026.

Where this paper and its answers come from

SSC does not publish CGL question papers or a public answer key. The questions and options here are reproduced as printed on a candidate's own response sheet for this shift — the Commission's text, unchanged. Each answer is SSC's tentative key as marked on that sheet; SSC allowed challenges to it and never publishes a final key. The solutions are written by UnlockIAS.

What is the product formed when zinc and sulphuric acid react?

(a)Zinc oxide
(b)Zinc sulphide
(c)Zinc sulphate
(d)Zinc hydroxide

Answer

Why

Correct — C. A metal reacting with a dilute acid gives a salt plus hydrogen.

Zn + H₂SO₄ → ZnSO₄ + H₂↑

The salt of sulphuric acid is a sulphate, so the salt formed here is zinc sulphate — option (c). The hydrogen leaves as a gas, which is the fizzing you see at the metal's surface.

Why the others are wrong

(a)
Zinc oxide — Zinc oxide (ZnO) comes from burning zinc in air or roasting its ore. That is an oxygen reaction, not an acid one.
(b)
Zinc sulphide — Zinc sulphide (ZnS) is the mineral zinc blende, made from zinc and sulphur directly. Sulphuric acid supplies the sulphate ion, not the sulphide ion.
(d)
Zinc hydroxide — Zinc hydroxide needs a hydroxide source such as sodium hydroxide solution. An acid supplies hydrogen ions, so it cannot leave a hydroxide behind.

Concept

This is a displacement reaction. Zinc stands above hydrogen in the reactivity series, so it displaces hydrogen from the acid and takes its place in the salt.

What remains in solution is the metal cation paired with the acid's anion — zinc with sulphate. The freed hydrogen bubbles off.

The same template runs through the chapter: zinc with dilute HCl gives zinc chloride and hydrogen, magnesium with dilute H₂SO₄ gives magnesium sulphate and hydrogen.

The rule is written for dilute acids. Dilute nitric acid is the standard exception, because it oxidises the hydrogen to water instead of releasing it, and hot concentrated sulphuric acid behaves differently again.

Key facts

Zn + H₂SO₄ → ZnSO₄ + H₂, so the products are zinc sulphate and hydrogen gas.
Metal plus dilute acid gives salt plus hydrogen, provided the metal lies above hydrogen in the reactivity series.
The hydrogen released gives a pop sound when a burning splint is brought to its mouth.
Sulphuric acid yields sulphates, hydrochloric acid yields chlorides and nitric acid yields nitrates.

Study next

The reactivity series and which metals displace hydrogen from dilute acidsNaming a salt from its parent acid and parent baseLaboratory tests for hydrogen, oxygen and carbon dioxide

Common traps

Sulphide and sulphate differ by one syllable and by the whole reaction that produces them.
Assuming every metal-acid pair releases hydrogen, which fails for dilute nitric acid.

SSC asks this one reaction from both ends. Here the product salt is wanted; on 23 Sep 2024, 12:30, GA Q.9 the same reaction is asked for the gas evolved, keyed to hydrogen.

Related PYQs

No directly related past PYQ was found.