Ammonia Intex-1 Concise Class-10 ICSE Chemistry Selina Solutions Chapter-9. We Provide Step by Step Answer of Intex-1 Questions of Exercise-9 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.
Ammonia Intex-1 Concise Class-10 ICSE Chemistry Selina Solutions Chapter-9
| Board | ICSE |
| Book / Publication | Concise / Selina |
| Subject | Chemistry |
| Class | 10th |
| Writer | Dr SP Singh |
| Chapter-9 | Study of Compounds – Ammonia |
| Topics | Intex-1 |
| Edition | 2025-2026 |
Intex-1 Questions on Study of Compounds-Ammonia
Page-158
Que-1:
(a) State the type of bonding present in ammonia, show by a diagram?
(b) What is the formula of liquid ammonia? Account for the basic nature of this compound.
Ans:
(a) Covalent bonding is present in ammonia.
(b) Formula of liquid ammonia is: NH3.
Liquid ammonia is liquefied ammonia and is basic in nature. It dissolves in water to give ammonium hydroxide which ionizes to give hydroxyl ions.
NH3 + H2O → NH4OH
NH4OH ⇔ NH4++ OH–
Therefore it turns red litmus blue and phenolphthalein solution pink.
Que-2:
(a) Write a balanced chemical equation for the lab preparation of ammonia. (2018)
(b) How is ammonia dried and collected in the laboratory?
(c) Ammonia cannot be collected over water. Give reason.
Ans:
(a) Lab preparation of ammonia:
2NH4Cl+Ca(OH)2 → CaCl2 +2H2O +2NH3
(b) The ammonia gas is dried by passing through a drying tower containing lumps of quicklime (CaO).
(c) Ammonia is highly soluble in water and therefore it cannot be collected over water.
Que-3:
(a) Explain with a diagram the preparation of aqueous ammonia.
(b) Why are other drying agents such as P2O5 and CaCl2 not used to dry NH3
Ans:
(a) An aqueous solution of ammonia is prepared by dissolving ammonia in water. The rate of dissolution of ammonia to water is very high.
Diagram:
(b)The drying agent used is CaO in case of ammonia.
Other drying agents like P2O5 and CaCl2 are not used. As ammonia being basic reacts with them.
6NH3 + P2O5 +3H2O → 2(NH4)3PO4
CaCl2 + 4NH3 → CaCl2.4NH3
Que-4: A substance ‘A’ was heated with slaked lime and a gas ‘B’ with pungent smell was obtained. Name the substances A and B and give a balanced equation.
Ans: The substance A is Ammonium chloride and ‘B’ is Ammonia.
Reaction: 2NH4Cl + Ca(OH)2 → CaCl2 + 2H2O + 2NH3
Que-5: Ammonia is manufactured by Haber Process.
(a) Under what conditions do the reactants combine to form ammonia? Give a balanced equation for the reaction.
(b) In what ratio by volume, are the above gases used?
(c) State one possible source of each reactant used in Haber process.
(d) State whether the formation of ammonia is promoted by the use of high pressure or low pressure?
(e) Mention two possible ways by which ammonia produced is removed from unchanged gases.
(f) What is the function of:
(i) Finely divided iron
(ii) Molybdenum in the above process
(g) What is the percentage formation of ammonia?
(h) How can this percentage formation be increased?
Ans: (a) Conditions for reactants to combine :
Optimum temperature is 450o-500oC
Above 200 atm pressure
Finely divided iron as catalyst
Traces of molybdenum or Al2O3 as promoters.
Reaction: N2 +3H2 
2NH3 + heat
(b) Dry nitrogen and dry hydrogen in the ratio of 1:3 by volume is made to combine.
(c) Source of Hydrogen: Hydrogen is generally obtained from water gas by Bosch process.
(CO + H2) + H2O (Fe/F32O3) → (500ºC) CO2 +2 H2
Source of Nitrogen: It is obtained from fractional distillation of liquid air.
(d) High pressure favours the forward reaction i.e. formation of ammonia.
(e) Two possible ways by which NH3 produced is removed from unreacted N2 and H2 by:
(i) Liquefaction: NH3 is easily liquefiable.
(ii) Absorbing in water: As ammonia is highly soluble in water.
(f) (i) Finely divided iron increases the rate of reaction.
(ii) Molybdenum acts as a promoter to increase the efficiency of the catalyst.
(g) 15%
(h) The unchanged nitrogen and hydrogen are recirculated through the plant to get more ammonia. By recirculating in this way, an eventual yield of 98% can be achieved.
Que-6: Give reasons:
(a) Ammonium compounds do not occur as minerals.
(b) Ammonium nitrate is not used in the preparation of ammonia.
(c) Conc. H2SO4 is a good drying agent, yet it is not used to dry NH3.
(d) In the lab. preparation of ammonia
(i) calcium hydroxide is used in excess
(ii) a flask is fitted in slanting position
Ans:
(a) Ammonium compounds being highly soluble in water do not occur as minerals.
(b) Ammonium nitrate is not used in the preparation of ammonia as it is explosive in nature and it decomposes forming nitrous oxide and water vapours.
(c) Conc. H2SO4 is not used to dry ammonia, as ammonia being basic reacts with them.
2NH3 + H2SO4 → (NH4)2SO4
(d) (i) In order to better mixing of ammonium chloride, calcium hydroxide used in excess.
(ii) The flask is fitted in slatting position because of the water formed in the reaction does not trickle back into the heated flask.
Que-7: State the following conditions required in the above process
(i) Temperature
(ii) Pressure
(iii) Catalyst
Ans:
(i) 450 – 500°C
(ii) 200 – 800 atm
(iii) Finely divided iron (Fe)
Que-8: Choose the correct word or phrase from the brackets to complete the following sentences and write balanced equations for the same.
(a) Ammonium chloride is a soluble salt prepared by ………… [precipitation, neutralisation].
(b) When ammonium chloride is heated, it undergoes ………… [thermal decomposition / dissociation].
(c) Heating ammonium chloride with sodium hydroxide produces ………… [ammonia, nitrogen].
Ans:
(a) Neutralisation
(b) Thermal decomposition
(c) Ammonia
Que-9: An element has 2 electrons in its N shell. It reacts with a non-metal of atomic number 7. The compound formed reacts with warm water and produces a basic gas. Identify the elements and write the balanced chemical reaction.
Ans: An element has 2 electrons in its N shell = Ca (calcium)
It reacts with a non-metal of atomic number 7 = N (nitrogen)
The compound formed is calcium nitride (Ca3N2) which reacts with warm water and produces the basic gas ammonia (NH3).
Que-10: The following reactions are carried out:
A : Nitrogen + metal compound X
B: X+ water ammonia +another compound
C: Ammonia + metal oxide metal + water + N2
One metal that can be used for reaction A is magnesium.
(a) Write the formula of the compound X formed.
(b) Write the correctly balanced equation for reaction B where X is the compound formed.
(c) What property of ammonia is demonstrated by reaction C?
Ans:
(a) The formula of the compound is Mg3N2.
(b) Balanced equation :
Mg3N2 + 6 H2O → 3 Mg(OH)2 + 2 NH3
(c) Ammonia is a reducing agent and reduces less active metal oxide to its respective metal.
Que-11: Correct the following:
(a) A reddish brown precipitate is obtained when ammonium hydroxide is added to ferrous sulphate.
(b) Liquid ammonia is a solution of NH3.
(c) Finely divided platinum is used in the Haber process.
(d) Conc. H2SO4is a drying agent for NH3.
(e) Ammonium salts, on heating, decompose to give ammonia.
Ans:
(a) A reddish brown precipitate is obtained when ammonium hydroxide is added to ferrous chloride.
(b) Aqueous ammonia is a solution of NH3.
(c) Finely divided iron is used in Haber process.
(d) Quicklime (CaO) is a drying agent for NH3.
(e ) Ammonium salts, on thermal decomposition, give ammonia and hydrogen chloride
Que-12: Choose the correct from the following:
Ammonia can be obtained by adding water to
A : Ammonium chloride.
B : Ammonium nitrite.
C : Magnesium nitride.
D : Magnesium nitrate
Ans: Option C : Magnesium Nitride
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