Sulphuric Acid Short Ans Concise Class-10 ICSE Chemistry Selina Solutions Chapter-11. We Provide Step by Step Answer of Short Ans Questions of Exercise-11 for ICSE Class-10. The given Solutions is according to the Latest editions. Visit official Website CISCE for detail information about ICSE Board Class-10.

Sulphuric Acid Short Ans Concise Class-10 ICSE Chemistry Selina Solutions Chapter-11

Board	ICSE
Book / Publication	Concise / Selina
Subject	Chemistry
Class	10th
Writer	Dr SP Singh
Chapter-11	Study of Compounds – Sulphuric Acid
Topics	Short Ans
Edition	2025-2026

Short Ans Questions on Sulphuric Acid

Page-186

Que-1: Give reasons for the following.

(a) Sulphuric acid forms two types of salts with NaOH
(b) A piece of wood becomes black when concentrated sulphuric acid is poured on it
(c) Brisk effervescence is seen when oil of vitriol is added to sodium carbonate.

Ans:
(a) Two types of salts are formed when sulphuric acid reacts with NaOH because sulphuric acid is dibasic.
NaOH + H₂SO   → NaHSO₄ + H₂O
2NaOH + H₂SO₄    →   Na₂SO₄ + 2H₂O
(b) A piece of wood becomes black when concentrated sulphuric acid is poured on it because it gives a mass of carbon.
(c) When sulphuric acid is added to sodium carbonate it liberates carbon dioxide which produces brisk effervescence.
Na₂CO₃+H₂SO₄ →    Na₂SO₄ +H₂O+CO₂ ↑

Que-2: Why is water not added to concentrated H2SO4 in order to dilute it?

Ans: Water is not added to concentrated acid since it is an exothermic reaction. If water is added to the acid, there is a sudden increase in temperature and the acid being in bulk tends to spurt out with serious consequences.

Que-3: Why is:

(a) Concentrated sulphuric acid kept in air tight bottles?
(b) H₂SO₄ is not a drying agent for H₂S?
(c) Sulphuric acid used in the preparation of HCl and HNO₃? Give equation in both cases.

Ans:
(a) Concentrated sulphuric acid is hydroscopic substance that absorbs moisture when exposed to air. Hence, it is stored in air tight bottles.
(b) Sulphuric acid is not a drying agent for H₂S because it reacts with H₂S to form sulphur.
H₂SO₄+H₂S →  2H₂O+SO₂+S ↓
(c) Concentrated sulphuric acid has high boiling point (356^oC). So, it is considered to be non-volatile. Hence, it is used for preparing volatile acids like Hydrochloric acid and Nitric acids from their salts by double decomposition.
NaCl + H₂SO₄   →    NaHSO₄ +HCl
NaNO₃ + H₂SO₄   →     NaHSO₄ +HNO₃

Que-4: State your observation when –

(a) Sugar crystals are added to a hard glass test tube containing conc. sulphuric acid.
(b) Conc. H₂SO₄ is added to a crystal of hydrated copper sulphate.

Ans:
(a) Charring of sugar takes place. Sulphuric acid dehydrates sugar leaving behind carbon which is black in colour.
(b) The blue coloured hydrous copper sulphate changes to white anhydrous copper sulphate as the water of crystallization is removed.

Que-5: Give balanced equation(s) for :

(a) Reaction of dilute sulphuric acid when poured over sodium sulphite
(b) Manufacture of sulphuric acid by the Contact process.
(c) Heating sulphur with conc. sulphuric acid
(d) Dehydration of sugar crystals by conc. sulphuric acid
(e) Action of concentrated sulphuric acid on carbon.

Ans:
(a) Na₂SO₃ + H₂SO₄ (dil.) ⟶ Na₂SO₄ + H₂O + SO₂
(b) Contact process: Sulphur or Pyrite Burner:
S + O₂ ⟶ SO₂
4FeS₂ + 11O₂ ⟶ 2Fe₂O₃ + 8SO₂
(c) S + 2H₂SO₄ [conc.] ⟶ 3SO₂ + 2H₂O
(d) C < em > 12H </em> 22O₁₁ (s)  →  (Conc. H₂SO₄ ) 12C (s) + 11H₂O
(e) C + 2H₂SO₄ [conc.] ⟶ CO₂ + 2H₂O + 2SO₂

Que-6: Write the equations for the following reactions:

(a) dil. H₂SO₄ and barium chloride.
(b) dil. H₂SO₄ and sodium sulphide.
(c) Zinc sulphide and dilute sulphuric acid.

Ans:
(a) BaCl₂ + H₂SO₄ (dil) ⟶ 2HCl + BaSO₄ ↓ [white ppt. formed]
(b) Na₂S + H₂SO₄ ⟶ Na₂SO₄ + H₂S
(c) ZnS + H₂SO₄ (dil.) ⟶ ZnSO₄ + H₂S

Que-7: Dilute and concentrated sulphuric acid can be distinguished by using metals copper and zinc. Explain by giving balanced equations.

Ans: Conc. sulphuric acid acts as an oxidising agent and oxidises metals like copper and Zinc.
Cu + 2H₂SO₄ (conc.) ⟶ CuSO₄ + H₂O + 2SO₂ ↑
Zn + 2H₂SO₄ (conc.) ⟶ ZnSO₄ + H₂O + 2SO₂ ↑
alse, dil. sulphuric acid is not an oxidising agent and it cannot oxidise copper and zinc.
Therefore, Conc. sulphuric acid and dil. sulphuric acid can be distinguished by considering the oxidising property of sulphuric acid.

Que-8: Give two balanced reactions of each type to show the following properties of sulphuric acid.

(a) Acidic nature
(b) Oxidising agent
(c) dehydrating Nature
(d) Non-volatile nature

Ans: Balanced reactions are:
(a) Acidic nature:
(i) Dilute H₂SO₄ reacts with basic oxides to form sulphate and water.
2 NaOH+H₂SO₄ → Na₂SO₄+2H₂O
(ii) CuO+H₂SO₄ → CuSO₄+H₂O
(b) Oxidising agent:
H₂SO₄ → H₂O +SO₂ +[O]
Nascent oxygen oxidizes non-metals, metals and inorganic compounds.
For example,
Carbon to carbon dioxide
C+H₂SO₄ CO₂ +H₂O +2SO₂
Sulphur to sulphur dioxide
S + H₂SO₄ → 3SO₂ +2H₂O
(c) dehydrating Nature

(d) Non-volatile nature:
It has a high boiling point (356^oC) so it is considered to be non-volatile. Therefore, it is used for preparing volatile acids like hydrochloric acid, nitric acid from their salts by double decomposition reaction.
NaCl + H₂SO₄ ⟶ NaHSO₄ + HCl
KCl + H₂SO₄ ⟶ KHSO₄ + HCl

Que-9: Give a chemical test to distinguish between:

(a) Dilute sulphuric acid and dilute hydrochloric acid
(b) Dilute sulphuric acid and conc. sulphuric acid
(c) Dilute sulphuric acid and dilute hydrochloric acid [using barium chloride solution]

Ans:
(a) Bring a glass rod dipped in Ammonia solution near the mouth of each test tubes containing dil. Hel and dil. H₂SO₄each.

Dil HCl	Dil. H2SO4
White fumes of ammonium chloride	No such fumes

(b)
1. Dilute sulphuric acid treated with zinc gives Hydrogen gas which bums with pop sound.
Concentrated H₂SO₄ gives SO₂ gas with zinc and the gas turns Acidified potassium dichromate paper green.
2.Barium chloride solution gives white ppt. with dilute H₂SO₄, This white ppt. is insoluble in all acids.
Concentrated H₂SO₄ and NaCl mixture when heated gives dense white fumes if glass rod dipped in Ammonia solution is brought near it.
(c) Barium chloride soln. reacts with dilute sulphuric acid to give a white ppt. of barium sulphate but with dilute hydrochloric acid no white ppt. is produced since barium chloride is soluble in dil. sulphuric acid.

Que-10: State the conditions required for the conversion of sulphur dioxide to sulphur trioxide to take place:

Ans: The conditions for the conversion of sulphur dioxide to sulphur trioxide are:

1. Temperature: 450 to 500°C
2. Pressure: 1 to 2 atmosphere
3. Presence of Catalyst: Vanadium pentoxide (V₂O₅)
4. Excess of Oxygen

Que-11: Making use only of substances given: dil. sulphuric acid, Sodium carbonate, Zinc, Sodium Sulphite, Lead, Calcium carbonate:

Give equations for the reactions by which you could obtain:
(a) hydrogen
(b) sulphur dioxide
(c) carbon dioxide
(d) zinc carbonate (2 steps)

Ans:
(a) Zn + H₂SO₄  ⟶ ZnSO₄ + H₂
(b) Na₂SO₃ + H₂SO₄  ⟶ Na₂SO₄ + H₂O + SO₂
(c) Na₂CO₃ + H₂SO₄  ⟶ Na₂SO₄ + H₂O + CO₂
(d) Zn + H₂SO₄  ⟶ ZnSO₄ + H₂
ZnSO₄ + Na₂CO₃  ⟶ ZnCO₃ + Na₂SO₄

Que-12: Give equations for the action of sulphuric acid on

(i) Potassium hydrogen carbonate
(ii) Sulphur

Ans:
(i) Action of sulphuric acid on potassium hydrogen carbonate
2KHCO₃+ H₂SO₄→ K₂SO₄+ 2H₂O + 2CO₂↑
(ii) Action of sulphuric acid on sulphur
S + 2H₂SO₄→ 3SO₂ + 2H₂O

Que-13: In the manufacture of sulphuric acid by contact process, give the equations for the conversion of sulphur trioxide to sulphuric acid.

Ans: In the contact process for the manufacture of sulphuric acid, the equations for the conversion of sulphur trioxide to sulphuric acid are
SO₃ + H₂SO₄ → H₂S₂O₇
(oleum or pyro sulphuric acid)
H₂S₂O₇ + H₂O → 2H₂SO₄

Que-14: Give a balanced equation for the conversion of zinc oxide to zinc sulphate.

Ans: ZnO + H₂SO₄ [dil.] ⟶ ZnSO₄ + H₂O

—:  End of Study of Compounds – Sulphuric Acid Short Ans Concise Class-10 ICSE Chemistry Selina Solutions : –

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