Nitric Acid Intext-1 Concise Class-10 ICSE Chemistry Selina Solutions Chapter-10. We Provide Step by Step Answer of Intext-1 Questions of Exercise-10 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.

Nitric Acid Intext-1 Concise Class-10 ICSE Chemistry Selina Solutions Chapter-10

Board	ICSE
Book / Publication	Concise / Selina
Subject	Chemistry
Class	10th
Writer	Dr SP Singh
Chapter-10	Study of Compounds – Nitric Acid
Topics	Intext-1
Edition	2025-2026

Intext-1 Questions on Study of Compounds-Nitric Acid

Page-172

Que-1: Fill in the blank :

Cold, dil. nitric acid reacts with copper to form …………… (Hydrogen, nitrogen dioxide, nitric oxide).

Ans: Cold, dilute nitric acid reacts with copper to form nitric oxide.

Que-2: What is: (a) aqua fortis (b) aqua regia (c) Fixation of Nitrogen?

Ans:
(a) Aqua fortis: Nitric acid is called aqua fortis. Aqua fortis means strong water. It is so called because it reacts with nearly all metals.
(b) Aqua Regia: Conc. Nitric acid (1part by volume) when mixed with conc. Hydrochloric acid (3 parts by volume) gives a mixture called aqua regia. It means Royal water.
(c) Fixation of Nitrogen: The conversion of free atmospheric nitrogen into useful nitrogenous compounds in the soil is known as fixation of atmospheric nitrogen.

Que-3: During thunderstorm, rain water contains nitric acid. Explain with reactions.

Ans: During lightning discharge, the nitrogen present in the atmosphere reacts with oxygen to form nitric oxide.
N₂+ O₂     ⇔        2NO
Nitric oxide is further oxidized to nitrogen dioxide.
2NO +O₂      ⇔    2NO₂
The nitrogen dioxide dissolves in atmospheric moisture in the presence of oxygen of the air and forms nitric acid which is washed down by the rain and combines with the salt present on the surface of the earth.
4NO₂ + 2H₂O +O₂    →   4HNO₃

Que-4: Ammonia is used in the Ostwald process.

(a) Give the source of reactants used in the process.
(b) Name the catalyst used in the process.
(c) Name the oxidising agent used in this process.
(d) What is the ratio of ammonia and air taken in this process?
(e) Why is quartz used in the process?

Ans:
(a) A mixture of air and dry ammonia in the ratio of 10:1 by volume
(b) Platinum gauze
(c) Oxygen
(d) ammonia : dry air : : 1 : 10
(e) Quartz is acid resistant. When packed in layers, it helps in dissolving nitrogen dioxide uniformly in water.

Que-5: 

(a) Write a balanced chemical equation for the laboratory preparation of nitric acid.
(b) In the preparation of nitric acid from KNO₃, concentrated hydrochloric acid is not used in place of concentrated sulphuric acid. Explain why?
(c) Conc. Nitric acid prepared in the laboratory is yellow in colour .Why? How is this colour removed?
(d) Give reasons for the following:
In the laboratory preparation of nitric acid, the mixture of concentrated sulphuric acid and sodium nitrate should not be heated very strongly above 200^oC.

Ans:
(a) Chemical equation is:
KNO₃ +H₂SO₄        →  (200º)       KHSO₄ +HNO₃
(b) Concentrated hydrochloric acid cannot replace Conc. Sulphuric acid for the preparation of nitric acid because hydrochloric acid is volatile acid and hence nitric acid vapours will carry HCl vapours.
(c) Conc. Nitric acid prepared in the laboratory is yellow in colour due to the dissolution of reddish brown coloured nitrogen dioxide gas in acid. This gas is produced due to the thermal dissociation of a portion of nitric acid.
4HNO₃ → 2H₂O + 4NO₂ + O₂
The yellow colour of the acid is removed:
If dry air or CO₂ is bubbled through the yellow acid, the acid turns colourless because it drives out NO₂ from warm acid which is further oxidized to nitric acid.
By addition of excess of water, nitrogen dioxide gas dissolves in water and thus the yellow colour of the acid is removed.
(d) The temperature of the mixture of concentrated sulphuric acid and sodium nitrate should not exceed 200^oC because sodium sulphate formed at higher temperature forms a hard crust which sticks to the walls of the retort and is difficult to remove. At higher temperature nitric acid may also decompose.
NaNO₃ + NaHSO₄   → (200ºC)   Na₂SO₄ + HNO₃

Que-6: 

(a) Nitric acid cannot be concentrated beyond 68% by the distillation of dilute solution of HNO₃. State the reason.
(b) What is passive iron? How is passivity removed?

Ans:
(a)  Nitric acid forms a constant boiling mixture with water containing 68% acid. This mixture boils constantly at constant boiling point without any change in its composition. At this temperature, the gas and the water vapour escape together. Hence the composition of the solution remains unchanged. So nitric acid cannot be concentrated beyond 68% by distillation of dilute solution of HNO₃.
(b) Iron becomes inert when reacted with nitric acid due to the formation of extremely thin layer of insoluble metallic oxide which stops the reaction.
Passivity can be removed by rubbing the surface layer with the sand paper or by treating with strong reducing agent.

Que-7: Name the product formed when :

(a) Carbon and conc. Nitric acid is heated
(b) Dilute HNO₃ is added to copper.

Ans:
(a) When carbon and conc. Nitric acid is heated the products formed are Carbon dioxide, Nitrogen dioxide and water.
C + 4HNO₃ CO₂ + 2H₂O +4NO₂
(b) Copper when reacts with dilute HNO₃ forms Copper nitrate, Nitric oxide and water.
3Cu + 8 HNO₃ 3Cu(NO₃) ₂ +4H₂O + 2NO

Que-8: Give two chemical equations for each of the following:

(a) Reactions of nitric acid with non-metals.
(b) Nitric acid showing acidic character.
(c) Nitric acid acting as oxidizing agent.

Ans:
(a) Reaction of nitric acid with non-metals:
C + 4HNO₃ ⟶ CO₂ + 2H₂O + 4NO₂
S + 6HNO₃ ⟶ H₂SO₄ + 2H₂O + 6NO₂
(b) Nitric acid showing acidic character:
K₂O + 2HNO₃ ⟶ 2KNO₃ + H₂O
CuO + 2HNO₃ ⟶ Cu(NO₃)₂ + H₂O
(c) Nitric acid acting as oxidizing agent
C + 4HNO₃ ⟶ CO₂ + 2H₂O + 4NO₂
3Cu + 8HNO₃ [cold and dil.] ⟶ 3Cu(NO₃)₂ + 4H₂O + 2NO

Que-9: Write the balanced equations and name the products formed when :

(a) Sodium hydrogen carbonate is added to nitric acid.
(b) Cupric oxide reacts with dilute nitric acid.
(c) Zinc reacts with dilute nitric acid.
(d) Concentrated nitric acid is heated.

Ans:
(a) When Sodium hydrogen carbonate is added to nitric acid sodium nitrate, carbon dioxide and water is formed.
NaHCO₃ + HNO₃ ⟶ NaNO₃ + H₂O + CO₂ ↑
(b) When Cupric oxide reacts with dilute nitric acid, it forms Copper nitrate.
CuO +2HNO₃  ⟶  Cu(NO₃)₂ +H₂O
(c) Zinc reacts with nitric acid to form Zinc nitrate, nitric oxide and water.
3 Zn +8HNO₃   ⟶    3Zn(NO₃)₂ +4H₂O +2NO
(d) 4HNO₃  ⟶  2H₂O + 4NO₂ + O₂

Que-10: How will you prepare the following from nitric acid?

(a) Sodium nitrate
(b) Copper nitrate
(c) Lead nitrate
(d) Magnesium nitrate
(e) Ferric nitrate
(f) Aqua regia

Ans:
(a) Sodium nitrate:
NaOH + HNO₃ [dil.] ⟶ NaNO₃ + H₂O
Sodium hydroxide reacts with nitric acid to form sodium nitrate.
(b) Copper nitrate:
CuO + 2HNO₃ [dil.] ⟶ Cu(NO₃)₂ + H₂O
Copper oxide reacts with nitric acid to form copper nitrate.
(c) Lead nitrate:
Pb + 4HNO₃ [conc.] ⟶ Pb(NO₃)₂ + 2H₂O + 2NO₂
Lead reacts with conc. nitric acid to form lead nitrate.
(d) Magnesium nitrate:
Mg(OH)₂ + 2HNO₃ [dil.] ⟶ Mg(NO₃)₂ + 2H₂O
Magnesium with dil. nitric acid to form magnesium nitrate.
(e) Ferric nitrate:
Fe + 6HNO₃ [conc.] ⟶ Fe(NO₃)₃ + 3H₂O + 3NO₂
Iron reacts with conc. nitric acid to form ferric nitrate.
(f) Aqua regia:
3HCl + HNO₃ ⟶ NOCl + 2H₂O + 2[Cl]
Nitric acid reacts with hydrochloric acid to form a mixture called aqua regia.

Que-11: Write the equation for following conversions A, B , C and D.

Ans:
A: Copper can be converted into copper nitrate.
3Cu + 8HNO₃    ⟶   3Cu(NO₃)₂ + 4H₂O+ 2NO
B:2Cu(NO₃)₂    ⟶   2CuO + 4NO₂ + O₂
C:2Cu+ O₂   ⟶   2CuO
D:By reduction
2CuO + C   ⟶    2Cu + CO₂

Que-12: Correct the following , if required:

(a) HNO₃ is a strong reducing agent.
(b) NaNO₃ gives NO₂ and O₂ on heating.
(c) Constant boiling nitric acid contains 80% nitric acid by weight.
(d) Nitric acid remains colourless even when exposed to light.
(e) Magnesium reacts with nitric acid to liberate hydrogen gas.

Ans: 
(a) HNO₃ is strong oxidizing agent.
(b) NaNO₃ gives NaNO₂ and oxygen on heating.
(c) Constant boiling nitric acid contains 68% nitric acid by weight.
(d) Nitric acid turns yellow solution when exposed to light.
(e) Magnesium reacts with very dilute (about 1%) nitric acid to liberate hydrogen gas.

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