Chapter 7B

Study of Compounds — Ammonia

Class 10 – Dalal Simplified ICSE Chemistry Solutions

Equation Worksheet

Question 1

Preparation of ammonia

Ammonia	Complete and balance the equations
Laboratory preparation [from ammonium salts]
1. Ammonium chloride + alkali	NH₄Cl + Ca(OH)₂ ⟶ …………… + H₂O + …………… [g]
2. Ammonium chloride + alkali	NH₄Cl + NaOH ⟶ …………… + H₂O + …………… [g]
3. Ammonium sulphate + alkali	(NH₄)₂SO₄ + NaOH ⟶ …………… + H₂O + …………… [g]
4. Ammonium sulphate + alkali	(NH₄)₂SO₄ + Ca(OH)₂ ⟶ …………… + H₂O + …………… [g]
Reactions of ammonia with drying agents
5. Sulphuric acid [conc.]	NH₃ + H₂SO₄ ⟶ ……………
6. Phosphorus pentaoxide	NH₃ + P₂O₅ + H₂O ⟶ ……………
7. Calcium chloride	NH₃ + CaCl₂ ⟶ ……………
Laboratory preparation [from metal nitrides]
8. Magnesium nitride	Mg₃N₂ + H₂O ⟶ …………… + …………… [g]
9. Calcium nitride	Ca₃N₂ + H₂O ⟶ …………… + …………… [g]
10. Aluminium nitride	AlN + H₂O ⟶ …………… + …………… [g]
Manufacture of ammonia
11. Haber’s process	N₂ + H₂ ⇌ …………… + Δ Temperature …………… Pressure …………… Catalyst …………… Promoter …………… Favourable conditions : …………… [temperature (high/low)] …………… [pressure (high/low)]

Answer

Ammonia	Complete and balance the equations
Laboratory preparation [from ammonium salts]
1. Ammonium chloride + alkali	2NH₄Cl + Ca(OH)₂ ⟶ *CaCl₂* + 2H₂O + *2NH₃* [g]
2. Ammonium chloride + alkali	NH₄Cl + NaOH ⟶ *NaCl* + H₂O + *NH₃* [g]
3. Ammonium sulphate + alkali	(NH₄)₂SO₄ + 2NaOH ⟶ *Na₂SO₄* + 2H₂O + *2NH₃* [g]
4. Ammonium sulphate + alkali	(NH₄)₂SO₄ + Ca(OH)₂ ⟶ *CaSO₄* + 2H₂O + *2NH₃* [g]
Reactions of ammonia with drying agents
5. Sulphuric acid [conc.]	2NH₃ + H₂SO₄ ⟶ *(NH₄)₂SO₄*
6. Phosphorus pentaoxide	6NH₃ + P₂O₅ + 3H₂O ⟶ *2(NH₄)₃PO₄*
7. Calcium chloride	8NH₃ + CaCl₂ ⟶ *CaCl₂.8NH₃*
Laboratory preparation [from metal nitrides]
8. Magnesium nitride	Mg₃N₂ + 6H₂O ⟶ *3Mg(OH)₂* + *2NH₃* [g]
9. Calcium nitride	Ca₃N₂ + 6H₂O ⟶ *3Ca(OH)₂* + *2NH₃* [g]
10. Aluminium nitride	AlN + 3H₂O ⟶ *Al(OH)₃* + *NH₃* [g]
Manufacture of ammonia
11. Haber’s process	N₂ + 3H₂ ⇌ *2NH₃* + Δ Temperature *450-500°C* Pressure *200-900 atmospheres* Catalyst *Finely divided iron [Fe]* Promoter *Molybdenum [Mo]* Favourable conditions : *low* temperature *high* pressure

Question 2

Chemical properties of ammonia

Ammonia	Complete and balance the equations
Combustibility
12. Burning of ammonia in oxygen	NH₃ + O₂ ⟶ …………… + ……………
13. Catalytic oxidation of ammonia	$NH_{3} + O_{2} Pt.$

$800° C \dots\dots\dots\dots\dots + \dots\dots\dots\dots\dots + Δ$
Basic nature Reaction of ammonia gas with
14. Hydrochloric acid	NH₃ + HCl ⟶ ……………
15. Nitric acid	NH₃ + HNO₃ ⟶ ……………
16. Sulphuric acid	NH₃ + H₂SO₄ ⟶ ……………
17. Water [Dissociation of aq. soln.]	NH₃ + H₂O ⟶ …………… [NH₄OH ⇌ NH₄⁺ + …………… ]
Reaction of ammonia [aq. soln.] with
18. Hydrochloric acid	NH₄OH + HCl ⟶ …………… + ……………
19. Nitric acid	NH₄OH + HNO₃ ⟶ …………… + ……………
20. Sulphuric acid	NH₄OH + H₂SO₄ ⟶ …………… + ……………
Reaction of ammonia [aq. soln.] with metallic salt solutions
21. Iron [II] sulphate	FeSO₄ + NH₄OH ⟶ …………… + …………… ↓
22. Iron [III] chloride	FeCl₃ + NH₄OH ⟶ …………… + …………… ↓
23. Lead nitrate	Pb(NO₃)₂ + NH₄OH ⟶ …………… + …………… ↓
24. Zinc sulphate	ZnSO₄ + NH₄OH ⟶ …………… + ……………↓ [Zn(OH)₂ + (NH₄)₂SO₄ + 2NH₄OH ⟶ …………… + H₂O]
25. Copper sulphate	CuSO₄ + NH₄OH ⟶ …………… + …………… ↓ [Cu(OH)₂ + (NH₄)₂SO₄ + 2NH₄OH ⟶ …………… + H₂O]

Answer

Ammonia	Complete and balance the equations
Combustibility
12. Burning of ammonia in oxygen	4NH₃ + 3O₂ ⟶ *2N₂* + *6H₂O*
13. Catalytic oxidation of ammonia	$4 NH_{3} + 5 O_{2} Pt.$

$800° C 4NO + 6H_{2} O + Δ$
Basic nature Reaction of ammonia gas with
14. Hydrochloric acid	NH₃ + HCl ⟶ *NH₄Cl*
15. Nitric acid	NH₃ + HNO₃ ⟶ *NH₄NO₃*
16. Sulphuric acid	2NH₃ + H₂SO₄ ⟶ *(NH₄)₂SO₄*
17. Water [Dissociation of aq. soln.]	NH₃ + H₂O ⟶ *NH₄OH* [NH₄OH ⇌ NH₄⁺ + *OH^–*]
Reaction of ammonia [aq. soln.] with
18. Hydrochloric acid	NH₄OH + HCl ⟶ *NH₄Cl* + *H₂O*
19. Nitric acid	NH₄OH + HNO₃ ⟶ *NH₄NO₃* + *H₂O*
20. Sulphuric acid	2NH₄OH + H₂SO₄ ⟶ *(NH₄)₂SO₄* + *2H₂O*
Reaction of ammonia [aq. soln.] with metallic salt solutions
21. Iron [II] sulphate	FeSO₄ + 2NH₄OH ⟶ *(NH₄)₂SO₄* + *Fe(OH)₂* ↓
22. Iron [III] chloride	FeCl₃ + 3NH₄OH ⟶ *3NH₄Cl* + *Fe(OH)₃* ↓
23. Lead nitrate	Pb(NO₃)₂ + 2NH₄OH ⟶ *2NH₄NO₃* + *Pb(OH)₂* ↓
24. Zinc sulphate	ZnSO₄ + 2NH₄OH ⟶ *(NH₄)₂SO₄* + *Zn(OH)₂* ↓ [Zn(OH)₂] + (NH₄)₂SO₄ + 2NH₄OH ⟶ *[Zn(NH₃)₄]SO₄* + 4H₂O
25. Copper sulphate	CuSO₄ + 2NH₄OH ⟶ *(NH₄)₂SO₄* + *Cu(OH)₂* + ↓ [Cu(OH)₂ + (NH₄)₂SO₄ + 2NH₄OH ⟶ *Cu(NH₃)₄SO₄* + 4H₂O]

Question 3

As a reducing agent [ammonia gas]

Ammonia	Complete and balance the equations
26. Heated copper oxide	CuO + NH₃ ⟶ …………… + H₂O + …………… [g]
27. Heated lead oxide	PbO + NH₃ ⟶ …………… + H₂O + …………… [g]
28. Chlorine [ammonia in excess]	NH₃ + Cl₂ ⟶ …………… + N₂ [g] NH₃ + HCl ⟶ …………… ______________________________________ 8NH₃ + Cl₂ ⟶ …………… + …………… [g]
29. Chlorine [chlorine in excess]	NH₃ + Cl₂ ⟶ …………… + …………… [g]

Answer

Ammonia	Complete and balance the equations
26. Heated copper oxide	3CuO + 2NH₃ ⟶ *3Cu* + 3H₂O + N₂ [g]
27. Heated lead oxide	3PbO + 2NH₃ ⟶ *3Pb* + 3H₂O + N₂ [g]
28. Chlorine [ammonia in excess]	2NH₃ + 3Cl₂ ⟶ *6HCl* + N₂ [g] 6NH₃ + 6HCl ⟶ *6NH₄Cl* ______________________________________ 8NH₃ + 3Cl₂ ⟶ *6NH₄Cl* + N₂ [g]
29. Chlorine [chlorine in excess]	NH₃ + 3Cl₂ ⟶ *3HCl* + *NCl₃* [g]

Question 1(2004)

From NH₃, HCl, H₂S, SO₂ – Select :

(i) The gas which when bubbled through CuSO₄ soln., a deep blue coloured soln. is formed.

(ii) This gas burns in oxygen with a green flame.

Answer

(i) Ammonia (NH₃)

CuSO₄ + 2NH₄OH [ammonia soln.]⟶ (NH₄)₂SO₄ + Cu(OH)₂
Cu(OH)₂ + (NH₄)₂SO₄ + 2NH₄OH ⟶ [Cu(NH₃)₄]SO₄ + 4H₂O

(ii) Ammonia (NH₃)

4NH₃ + 3O₂ ⟶ 2N₂ + 6H₂O

Question 2(2004)

Write the equation for the reaction in the Haber’s process that forms ammonia.

Answer

N₂ + 3H₂ ⇌ 2NH₃ + Δ

Question 3(2004)

State the purpose of liquefying the ammonia produced in the Haber’s process.

Answer

Liquefaction is a technique used for separating ammonia from the uncombined N₂ and H₂ reactant mixture during Haber’s process.

Question 4(2004)

Write an equation for the reaction of chlorine with excess of ammonia.

Answer

8NH₃ [excess] + 3Cl₂ ⟶ 6NH₄Cl + N₂

Question 1(2005)

Name the ion other than ammonium ion formed when ammonia dissolves in water.

Answer

Hydroxyl ion [OH^-1]

NH₃ + H₂O ⟶ NH₄OH

NH₄OH ⇌ NH₄⁺ + OH^-1

Question 2(2005)

Write equations for the formation of ammonia.

(i) NH₄Cl and slaked lime are heated.

(ii) Aluminium nitride and water.

Answer

(i) 2NH₄Cl + Ca(OH)₂ ⟶ CaCl₂ + 2H₂O + 2NH₃

(ii) AlN + 3H₂O ⟶ Al(OH)₃ + NH₃ [g]

Question 1(2006)

Select from the list — Ammonia, Copper oxide, Copper sulphate, Hydrogen chloride, Hydrogen sulphide, Lead bromide : The compound which is not a metal hydroxide but it’s aqueous solution is alkaline in nature.

Answer

Ammonia.

Reason — The aq. soln. of ammonia [NH₄OH] is alkaline in nature due to the presence of hydroxyl ions [OH^–]

NH₃ + H₂O ⟶ NH₄OH

NH₄OH ⇌ NH₄⁺ + OH^-1

Question 2(2006)

From the substances — Ammonium sulphate, Lead carbonate, Chlorine, Copper nitrate, Iron [II] sulphate — State : A compound which on heating with NaOH produces a gas which forms dense white fumes with HCl.

Answer

Ammonium sulphate.

Reason — Ammonia gas is produced when ammonium sulphate reacts with NaOH. Ammonia gas forms dense white fumes with HCl.

(NH₄)₂SO₄ + 2NaOH ⟶ Na₂SO₄ + 2H₂O + 2NH₃[g]

Question 3(2006)

State what is observed when excess of ammonia is passed through an aq. solution of lead nitrate.

Answer

Lead hydroxide is precipitated, chalky white in colour and is insoluble in excess of ammonium hydroxide soln.

Pb(NO₃)₂ + 2NH₄OH ⟶ 2NH₄NO₃ + Pb(OH)₂ ↓

Question 4(2006)

Name the substance used for drying ammonia.

Answer

Quicklime (CaO) is used for drying ammonia.

Question 5(2006)

Write a balanced chemical equation to illustrate the reducing nature of ammonia.

Answer

Ammonia gas is a strong reducing agent. Below equation shows reduction of Black Copper [II] oxide to brown Copper by Ammonia.

2NH₃ + 3CuO ⟶ 3Cu + 3H₂O + N₂ [g]

Question 6(2006)

With reference to Haber’s process, write the equation and the conditions required.

Answer

Nitrogen reacts with hydrogen under specific conditions liberating ammonia

N₂ + 3H₂ ⇌ 2NH₃ + Δ

Conditions :

Temperature : 450-500°C [Optimum temperature]

Pressure : 200 to 900 atmospheres [Optimum pressure]

Catalyst : Finely divided iron [Fe]

Promotor : Molybdenum [Mo] [Catalyst – iron [III] oxide [Fe₂O₃] may also be used containing promoters about 1% K₂O and 3% Al₂O₃]

Precautions : Impurities like CO, CO₂, and H₂S may poison the catalyst hence, the nitrogen-hydrogen reactant mixture must be free from them.

Question 1(2007)

Give an equation for formation of ammonium sulphate from ammonia and dilute sulphuric acid.

Answer

2NH₃ + H₂SO₄ (dil.) ⟶ (NH₄)₂SO₄

Question 2(2007)

Give equation for – reaction in which NH₃ is oxidized by :

(i) a metal oxide

(ii) a gas which is not oxygen

Answer

(i) 2NH₃ + 3CuO ⟶ 3Cu + 3H₂O + N₂ [g]

(ii) 8NH₃ [excess] + 3Cl₂ ⟶ 6NH₄Cl + N₂

Question 3(2007)

You enter a laboratory after a class has completed the Fountain Experiment. How will you be able to tell whether the gas used in the experiment was hydrogen chloride or ammonia.

Answer

If dry ammonia gas is present in the round bottom flask, the red litmus soln. kept in the trough below emerges out as a blue fountain since ammonia gas is basic in nature. On the other hand, if dry HCl was used in the flask instead of ammonia, the blue litmus soln. kept in the trough below, emerges out as a red fountain since HCl is acidic in nature.

Question 1(2008)

Ammonia can be obtained by adding water to : [Select the correct word]

Ammonium chloride
Ammonium nitrite
Magnesium nitride
Magnesium nitrate

Answer

Magnesium nitride
Mg₃N₂ + 6H₂O ⟶ 3Mg(OH)₂ + 2NH₃ [g]

Question 2(2008)

Name : An alkaline gas ‘A’ which gives dense white fumes with hydrogen chloride.

Answer

NH₃ (Ammonia)
NH₃ + HCl ⟶ NH₄Cl

Question 3(2008)

Write the equation for the following reaction : Aluminium nitride and water.

Answer

AlN + 3H₂O ⟶ Al(OH)₃ + NH₃ [g]

Question 4(2008)

Complete the table relating to an important industrial processes. [Output refers to the product of the process].

Name of process	Inputs	Catalyst	Equation for catalyzed reaction	Output
Haber process	Hydrogen +

Answer

Completed table is shown below:

Name of process	Inputs	Catalyst	Equation for catalyzed reaction	Output
Haber process	Hydrogen + *Nitrogen*	*Iron + Molybednum (promoter)*	*N₂ + 3H₂ ⇌ 2NH₃ + Δ*	*Ammonia*

Question 1(2009)

Name the gas – that burns in oxygen with a green flame.

Answer

Ammonia (NH₃)
4NH₃ + 3O₂ ⟶ 2N₂ + 6H₂O

Question 2(2009)

Write a fully balanced equation for — Magnesium nitride is treated with warm water.

Answer

Mg₃N₂ + 6H₂O ⟶ 3Mg(OH)₂ + 2NH₃ [g]

Question 3(2009)

Identity the substances ‘Q’ based on the information given — The white crystalline solid ‘Q’ is soluble in water. It liberates a pungent smelling gas when heated with sodium hydroxide solution.

Answer

Substances ‘Q’ are Ammonium salts like ammonium chloride, ammonium sulphate. They are white solids, soluble in water and liberate pungent smelling ammonia gas on heating with alkalis like NaOH.

Question 1(2010)

Complete the blanks (a) to (e) in the passage given, using the following words. [Ammonium, reddish brown, hydroxyl, nitrogen dioxide, ammonia, dirty green, alkaline, acidic]. In the presence of a catalyst, nitrogen and hydrogen combine to give (a) ………….. gas. When the same gas is passed through water, it forms a soln. which will be (b)………….. in nature, and will contain the ions (c) ………….. and (d) ………….. .(e) A ………….. coloured ppt. of iron [II] hydroxide is formed when the above solution is added to iron [II] sulphate solution.

Answer

(a) Ammonia

(b) Alkaline

(d) Hydroxyl

(e) Dirty green

Question 2(2010)

State your observation when — in the absence of catalyst, ammonia is burnt in an atmosphere of oxygen.

Answer

Green or greenish yellow flame is seen when ammonia gas is burnt in an atmosphere of oxygen. The reaction of combustion of Ammonia is:

4NH₃ + 3O₂ ⟶ 2N₂ + 6H₂O

Question 3(2010)

Give the equation for the reaction — ammonium chloride is heated with sodium hydroxide.

Answer

NH₄Cl + NaOH ⟶ NaCl + H₂O + NH₃

Question 4(2010)

In the manufacture of ammonia:

(i) Name the process.

(ii) State the ratio of the reactants taken?

(iii) State the catalyst used.

(iv) Give the equation for the manufacture of the gas ammonia.

Answer

(i) Haber’s Process

(ii) Nitrogen (N₂) and hydrogen (H₂) in the ratio 1:3 by volume

(iii) Finely divided iron (Fe)

(iv) N₂ + 3H₂ ⇌ 2NH₃ + Δ

Question 5(2010)

Write a relevant equation, to show that ammonia can act as a reducing agent

Answer

Ammonia gas is a strong reducing agent. Below equation shows reduction of Black Copper [II] oxide to brown Copper by Ammonia.

2NH₃ + 3CuO ⟶ 3Cu + 3H₂O + N₂ [g]

Question 6(2010)

Name two gases which can be used to study the fountain experiment. State the common property demonstrated by the fountain experiment ?

Answer

Hydrogen chloride gas (HCl) and Ammonia (NH₃) are the two gases which can be used to study the fountain experiment.

The common property demonstrated by the fountain experiment is the solubility of gases.

Question 1(2011)

State what is observed when – Ammonium hydroxide is first added in a small quantity and then in excess to a solution of copper sulphate.

Answer

Ammonium hydroxide if first added in small quantity and then in excess to a solution of copper sulphate, a pale blue ppt. of copper hydroxide is formed which dissolves in excess of ammonium hydroxide forming a soluble complex salt.

CuSO₄ + 2NH₄OH ⟶ (NH₄)₂SO₄ + Cu(OH)₂ ↓

Cu(OH)₂ + (NH₄)₂SO₄ + 2NH₄OH ⟶ [Cu(NH₃)₄]SO₄ + 4H₂O

Question 2(2011)

The diagram shows set up for the lab. preparation of a pungent alkaline gas.

(i) Name the gas collected in the jar.

(ii) Give a balanced equation for the above preparation

(iii) State how the above gas is collected?

(iv) Name the drying agent used.

(v) State how you will find out that the jar is full of the pungent gas?

Answer

(i) Ammonia (NH₃) gas is collected.

(ii) 2NH₄Cl + Ca(OH)₂ ⟶ CaCl₂ + 2H₂O + 2NH₃

(iii) Downward displacement of air is the method used to collect the gas.

(iv) Quicklime (CaO) is the drying agent.

(v) A glass rod dipped in conc. HCl acid is brought near the mouth of the jar. If the jar is full-dense white fumes of ammonium chloride are formed.

Question 3(2011)

Write a balanced chemical equation – Chlorine reacts with excess of ammonia.

Answer

8NH₃ [excess] + 3Cl₂ ⟶ 6NH₄Cl + N₂

Question 4(2011)

State your observation – Water is added to the product formed, when Al is burnt in a jar of nitrogen gas.

Answer

When Al metal is burnt in a jar of nitrogen gas, its nitride i.e., AlN is formed. When warm water AlN, it undergoes hydrolysis and is decomposed by warm water to give pungent smelling ammonia gas. The corresponding insoluble metal hydroxide (i.e., Al(OH)₃) is precipitated out. The reactions are shown below:

2Al + N₂ ⟶ 2AlN

AlN + 3H₂O ⟶ Al(OH)₃ + NH₃ [g]

Question 1(2012)

Name the gas produced when excess ammonia reacts with chlorine.

Answer

Nitrogen

8NH₃ [excess] + 3Cl₂ ⟶ 6NH₄Cl + N₂

Question 2(2012)

Rewrite the correct statement with the missing word/s — Magnesium nitride reacts with water to liberate ammonia.

Answer

Magnesium nitride reacts with warm water to liberate ammonia along with magnesium hydroxide.

Question 3(2012)

Give balanced equation for the reaction : Ammonia and Oxygen in the presence of a catalyst.

Answer

Below is the equation for the catalytic oxidation of Ammonia:

$4 NH_{3} + 5 O_{2} Pt.$

$800° C 4NO + 6H_{2} O + Δ$

Question 4(2012)

The following questions are based on the preparation of ammonia gas in the laboratory:

(i) Explain why ammonium nitrate is not used in the preparation of ammonia.

(ii) Name the compound normally used as a drying agent during the process.

(iii) How is ammonia gas collected? Explain why it is not collected over water.

Answer

(i) As ammonium nitrate is explosive in nature and may itself decompose forming nitrous oxide and water vapour, hence it is not used in the preparation of ammonia.

(ii) Quick lime [CaO] is used as a drying agent during the process.

(iii) Downward displacement of air is the method used for the collection of the ammonia gas. As ammonia gas is highly soluble in water, therefore, it is not collected over water.

Question 1(2013)

State one appropriate observation for : Excess of chlorine gas is reacted with ammonia gas.

Answer

Colourless ammonia gas reacts with greenish yellow excess chlorine giving a yellow explosive liquid (Nitrogen trichloride).

NH₃ + 3Cl₂ [excess] ⟶ 3HCl + NCl₃

Question 2(2013)

Nitrogen gas can be obtained by heating :

(a) Ammonium nitrate

(b) Ammonium nitrite

(d) Ammonium chloride

Answer

Ammonium nitrite

NH₄NO₂ ⟶ 2H₂O + N₂

Question 3(2013)

State two observations for : NH₄OH soln. is added to zinc nitrate soln. slowly and then in excess.

Answer

White gelatinous precipitate of zinc hydroxide is formed which dissolves in excess of NH₄OH solution.

Zn(NO₃)₂ + 2NH₄OH ⟶ 2NH₄NO₃ + Zn(OH)₂ ↓

Question 4(2013)

Give a balanced equation for : Reduction of hot Copper (II) oxide to copper using ammonia gas.

Answer

2NH₃ + 3CuO ⟶ 3Cu + 3H₂O + N₂ [g]

Question 5(2013)

State the – (i) Temperature (ii) Catalyst used in the Haber’s process for manufacture of ammonia. Give the equation for the catalyzed reaction.

Answer

(i) Temperature : 450 to 500°C [Optimum temperature]

(ii) Catalyst : Finely divided iron (Fe)

(iii) Equation : N₂ + 3H₂ ⇌ 2NH₃ + Δ

Question 6(2013)

Identify : An alkaline gas which produces dense white fumes when reacted with HCl gas.

Answer

Ammonia gas.

NH₃ + HCl ⟶ NH₄Cl

Question 1(2014)

Fill in the blank from the choices given in bracket : Ammonia gas is collected by ………….. (upward displacement of air, downward displacement of water, downward displacement of air)

Answer

Ammonia gas is collected by downward displacement of air.

Question 2(2014)

Write balanced equation for : Action of warm water on magnesium nitride.

Answer

Mg₃N₂ + 6H₂O ⟶ 3Mg(OH)₂ + 2NH₃ [g]

Question 3(2014)

Distinguish between the following pairs of compounds using the test given in bracket :

(i) Iron [II] sulphate and iron [III] sulphate [using ammonium hydroxide]

(ii) A lead salt and a zinc salt [using excess ammonium hydroxide]

Answer

(i) On reaction with ammonium hydroxide, Iron [II] sulphate forms a dirty green ppt whereas iron [III] sulphate forms a reddish brown ppt. Hence, the two can be distinguished easily.

FeSO₄ + 2NH₄OH ⟶ (NH₄)₂SO₄ + Fe(OH)₂ ↓

Fe₂(SO₄)₃ + 6NH₄OH ⟶ 3(NH₄)₂SO₄ + 2Fe(OH)₃ ↓

(ii) A lead salt gives a chalky white ppt. on reaction with ammonium hydroxide that is insoluble in excess of ammonium hydroxide. For example:

Pb(NO₃)₂ + 2NH₄OH ⟶ 2NH₄NO₃ + Pb(OH)₂ ↓

On the other hand, zinc salt forms a white gelatinous ppt. which dissolves when excess of ammonium hydroxide is added. Hence, the two can be distinguished.

ZnSO₄ + 2NH₄OH ⟶ (NH₄)₂SO₄ + Zn(OH)₂ ↓

[Zn(OH)₂] + (NH₄)₂SO₄ + 2NH₄OH ⟶ [Zn(NH₃)₄]SO₄ + 4H₂O

Question 4(2014)

State your observation : Calcium hydroxide is heated with ammonium chloride crystals.

Answer

Pungent smelling gas (ammonia) is given out.

2NH₄Cl + Ca(OH)₂ ⟶ CaCl₂ + 2H₂O + 2NH₃

Question 5(2014)

Name the other ion formed when ammonia dissolves in water. Give one test that can be used to detect the presence of the ion produced.

Answer

Hydroxyl ion [OH^-1] and ammonium ions [NH₄⁺] are formed.

NH₃ + H₂O ⟶ NH₄OH

NH₄OH ⇌ NH₄⁺ + OH^-1

The alkaline NH₄OH, due to the presence of hydroxyl ions [OH^–] turns red litmus blue and phenolphthalein soln. pink

Question 6(2014)

State the conditions required for : Catalytic oxidation of ammonia to nitric oxide.

Answer

Conditions for catalytic oxidation of ammonia to nitric oxide are :

Temperature : 800°C
Catalyst : Platinum (Pt)

$4 NH_{3} + 5 O_{2} Pt.$

$800° C 4NO + 6H_{2} O + Δ$

Question 1(2015)

From the list of the gases — Ammonia, ethane, hydrogen chloride, hydrogen sulphide, ethyne — Select the gas which is used as a reducing agent in reducing copper oxide to copper.

Answer

Ammonia

Reducing nature of ammonia:
2NH₃ + 3CuO ⟶ 3Cu + 3H₂O + N₂ [g]

Question 2(2015)

State one relevant observation — Ammonia gas is burnt in an atmosphere of excess oxygen.

Answer

4NH₃ + 3O₂ ⟶ 2N₂ + 6H₂O

Ammonia burns in the atmosphere of excess oxygen with a green or greenish yellow flame, forming nitrogen and water vapour.

Question 3(2015)

A metal ‘X’ has valency 2 and a non-metal ‘Y’ has a valency 3. If ‘Y ’ is a diatomic gas, write an equation for the direct combination of X and Y to from a compound.

Answer

X (metal) has a valency 2, hence,

X – 2e^– ⟶ X²⁺

Y (non metal) has a valency 3. hence,

Y + 3e^– ⟶ X^3-

Therefore, the two combine as :

3X + 2Y ⟶ X₃Y₂

Question 4(2015)

Give balanced chemical equations for —

(i) Lab. preparation of ammonia using an ammonium salt.

(ii) Reaction of ammonia with excess chlorine.

(iii) Reaction of ammonia with sulphuric acid.

Answer

(i) 2NH₄Cl + Ca(OH)₂ ⟶ CaCl₂ + 2H₂O + 2NH₃

(ii) NH₃ + 3Cl₂ [excess] ⟶ 3HCl + NCl₃

(iii) 2NH₃ + H₂SO₄ (dil.) ⟶ (NH₄)₂SO₄

Question 1(2016)

Write balanced equations for :

(i) Action of warm water on AlN.

(ii) Excess of ammonia is treated with chlorine.

(iii) An equation to illustrate the reducing nature of ammonia.

Answer

(i) AlN + 3H₂O ⟶ Al(OH)₃ + NH₃ [g]

(ii) 8NH₃ [excess] + 3Cl₂ ⟶ 6NH₄Cl + N₂

(iii) 2NH₃ + 3CuO ⟶ 3Cu + 3H₂O + N₂ [g]

Question 2(2016)

Name the gas evolved when the following mixtures are heated :

(i) Calcium hydroxide and Ammonium chloride.

(ii) Sodium nitrite and Ammonium chloride.

Answer

(i) Ammonia gas

2NH₄Cl + Ca(OH)₂ ⟶ CaCl₂ + 2H₂O + 2NH₃

(ii) Nitrogen gas

NH₄Cl + NaNO₂ ⟶ NaCl + NH₄NO₂

NH₄NO₂ ⟶ 2H₂O + N₂

Question 1(2017)

Write the balanced chemical equation for each of the following —

(i) Reaction of ammonia with heated copper oxide.

(ii) Laboratory preparation of ammonia from ammonium chloride.

Answer

(i) 2NH₃ + 3CuO ⟶ 3Cu + 3H₂O + N₂ [g]

(ii) 2NH₄Cl + Ca(OH)₂ ⟶ CaCl₂ + 2H₂O + 2NH₃

Question 2(2017)

State one relevant observation for the following reaction — Burning of ammonia in air.

Answer

Ammonia burns in the atmosphere of excess oxygen with a green or greenish yellow flame, forming nitrogen and water.

4NH₃ + 3O₂ ⟶ 2N₂ + 6H₂O

Question 3(2017)

Certain blanks spaces are left in the following tables as C, D & E. Identify each of them.

Lab preparation of	Reactants used	Products formed	Drying agent	Method of collection
NH₃ gas	C	Mg(OH)₂, NH₃	D	E

Answer

C : Magnesium nitride (Mg₃N₂) and water (H₂O).

D : Quick lime [CaO]

E : Downward displacement of air.

Question 4(2017)

Give a balanced chemical equation for each of the following —

(i) Catalytic oxidation of ammonia.

(ii) Reaction of ammonia with nitric acid.

Answer

(i) $4 NH_{3} + 5 O_{2} Pt.$

$800° C 4NO + 6H_{2} O + Δ$

(ii) NH₃ + HNO₃ ⟶ NH₄NO₃

Question 1(2013)

State one appropriate observation for : Excess of chlorine gas is reacted with ammonia gas.

Answer

Colourless ammonia gas reacts with greenish yellow excess chlorine giving a yellow explosive liquid (Nitrogen trichloride).

NH₃ + 3Cl₂ [excess] ⟶ 3HCl + NCl₃

Question 2(2013)

Nitrogen gas can be obtained by heating :

(a) Ammonium nitrate

(b) Ammonium nitrite

(d) Ammonium chloride

Answer

Ammonium nitrite

NH₄NO₂ ⟶ 2H₂O + N₂

Question 3(2013)

State two observations for : NH₄OH soln. is added to zinc nitrate soln. slowly and then in excess.

Answer

White gelatinous precipitate of zinc hydroxide is formed which dissolves in excess of NH₄OH solution.

Zn(NO₃)₂ + 2NH₄OH ⟶ 2NH₄NO₃ + Zn(OH)₂ ↓

Question 4(2013)

Give a balanced equation for : Reduction of hot Copper (II) oxide to copper using ammonia gas.

Answer

2NH₃ + 3CuO ⟶ 3Cu + 3H₂O + N₂ [g]

Question 5(2013)

State the – (i) Temperature (ii) Catalyst used in the Haber’s process for manufacture of ammonia. Give the equation for the catalyzed reaction.

Answer

(i) Temperature : 450 to 500°C [Optimum temperature]

(ii) Catalyst : Finely divided iron (Fe)

(iii) Equation : N₂ + 3H₂ ⇌ 2NH₃ + Δ

Question 6(2013)

Identify : An alkaline gas which produces dense white fumes when reacted with HCl gas.

Answer

Ammonia gas.

NH₃ + HCl ⟶ NH₄Cl

Question 1(2014)

Fill in the blank from the choices given in bracket : Ammonia gas is collected by ………….. (upward displacement of air, downward displacement of water, downward displacement of air)

Answer

Ammonia gas is collected by downward displacement of air.

Question 2(2014)

Write balanced equation for : Action of warm water on magnesium nitride.

Answer

Mg₃N₂ + 6H₂O ⟶ 3Mg(OH)₂ + 2NH₃ [g]

Question 3(2014)

Distinguish between the following pairs of compounds using the test given in bracket :

(i) Iron [II] sulphate and iron [III] sulphate [using ammonium hydroxide]

(ii) A lead salt and a zinc salt [using excess ammonium hydroxide]

Answer

(i) On reaction with ammonium hydroxide, Iron [II] sulphate forms a dirty green ppt whereas iron [III] sulphate forms a reddish brown ppt. Hence, the two can be distinguished easily.

FeSO₄ + 2NH₄OH ⟶ (NH₄)₂SO₄ + Fe(OH)₂ ↓

Fe₂(SO₄)₃ + 6NH₄OH ⟶ 3(NH₄)₂SO₄ + 2Fe(OH)₃ ↓

(ii) A lead salt gives a chalky white ppt. on reaction with ammonium hydroxide that is insoluble in excess of ammonium hydroxide. For example:

Pb(NO₃)₂ + 2NH₄OH ⟶ 2NH₄NO₃ + Pb(OH)₂ ↓

On the other hand, zinc salt forms a white gelatinous ppt. which dissolves when excess of ammonium hydroxide is added. Hence, the two can be distinguished.

ZnSO₄ + 2NH₄OH ⟶ (NH₄)₂SO₄ + Zn(OH)₂ ↓

[Zn(OH)₂] + (NH₄)₂SO₄ + 2NH₄OH ⟶ [Zn(NH₃)₄]SO₄ + 4H₂O

Question 4(2014)

State your observation : Calcium hydroxide is heated with ammonium chloride crystals.

Answer

Pungent smelling gas (ammonia) is given out.

2NH₄Cl + Ca(OH)₂ ⟶ CaCl₂ + 2H₂O + 2NH₃

Question 5(2014)

Name the other ion formed when ammonia dissolves in water. Give one test that can be used to detect the presence of the ion produced.

Answer

Hydroxyl ion [OH^-1] and ammonium ions [NH₄⁺] are formed.

NH₃ + H₂O ⟶ NH₄OH

NH₄OH ⇌ NH₄⁺ + OH^-1

The alkaline NH₄OH, due to the presence of hydroxyl ions [OH^–] turns red litmus blue and phenolphthalein soln. pink

Question 6(2014)

State the conditions required for : Catalytic oxidation of ammonia to nitric oxide.

Answer

Conditions for catalytic oxidation of ammonia to nitric oxide are :

Temperature : 800°C
Catalyst : Platinum (Pt)

$4 NH_{3} + 5 O_{2} Pt.$

$800° C 4NO + 6H_{2} O + Δ$

Question 1(2015)

From the list of the gases — Ammonia, ethane, hydrogen chloride, hydrogen sulphide, ethyne — Select the gas which is used as a reducing agent in reducing copper oxide to copper.

Answer

Ammonia

Reducing nature of ammonia:
2NH₃ + 3CuO ⟶ 3Cu + 3H₂O + N₂ [g]

Question 2(2015)

State one relevant observation — Ammonia gas is burnt in an atmosphere of excess oxygen.

Answer

4NH₃ + 3O₂ ⟶ 2N₂ + 6H₂O

Ammonia burns in the atmosphere of excess oxygen with a green or greenish yellow flame, forming nitrogen and water vapour.

Question 3(2015)

A metal ‘X’ has valency 2 and a non-metal ‘Y’ has a valency 3. If ‘Y ’ is a diatomic gas, write an equation for the direct combination of X and Y to from a compound.

Answer

X (metal) has a valency 2, hence,

X – 2e^– ⟶ X²⁺

Y (non metal) has a valency 3. hence,

Y + 3e^– ⟶ X^3-

Therefore, the two combine as :

3X + 2Y ⟶ X₃Y₂

Question 4(2015)

Give balanced chemical equations for —

(i) Lab. preparation of ammonia using an ammonium salt.

(ii) Reaction of ammonia with excess chlorine.

(iii) Reaction of ammonia with sulphuric acid.

Answer

(i) 2NH₄Cl + Ca(OH)₂ ⟶ CaCl₂ + 2H₂O + 2NH₃

(ii) NH₃ + 3Cl₂ [excess] ⟶ 3HCl + NCl₃

(iii) 2NH₃ + H₂SO₄ (dil.) ⟶ (NH₄)₂SO₄

Question 1(2016)

Write balanced equations for :

(i) Action of warm water on AlN.

(ii) Excess of ammonia is treated with chlorine.

(iii) An equation to illustrate the reducing nature of ammonia.

Answer

(i) AlN + 3H₂O ⟶ Al(OH)₃ + NH₃ [g]

(ii) 8NH₃ [excess] + 3Cl₂ ⟶ 6NH₄Cl + N₂

(iii) 2NH₃ + 3CuO ⟶ 3Cu + 3H₂O + N₂ [g]

Question 2(2016)

Name the gas evolved when the following mixtures are heated :

(i) Calcium hydroxide and Ammonium chloride.

(ii) Sodium nitrite and Ammonium chloride.

Answer

(i) Ammonia gas

2NH₄Cl + Ca(OH)₂ ⟶ CaCl₂ + 2H₂O + 2NH₃

(ii) Nitrogen gas

NH₄Cl + NaNO₂ ⟶ NaCl + NH₄NO₂

NH₄NO₂ ⟶ 2H₂O + N₂

Question 1(2017)

Write the balanced chemical equation for each of the following —

(i) Reaction of ammonia with heated copper oxide.

(ii) Laboratory preparation of ammonia from ammonium chloride.

Answer

(i) 2NH₃ + 3CuO ⟶ 3Cu + 3H₂O + N₂ [g]

(ii) 2NH₄Cl + Ca(OH)₂ ⟶ CaCl₂ + 2H₂O + 2NH₃

Question 2(2017)

State one relevant observation for the following reaction — Burning of ammonia in air.

Answer

Ammonia burns in the atmosphere of excess oxygen with a green or greenish yellow flame, forming nitrogen and water.

4NH₃ + 3O₂ ⟶ 2N₂ + 6H₂O

Question 3(2017)

Certain blanks spaces are left in the following tables as C, D & E. Identify each of them.

Lab preparation of	Reactants used	Products formed	Drying agent	Method of collection
NH₃ gas	C	Mg(OH)₂, NH₃	D	E

Answer

C : Magnesium nitride (Mg₃N₂) and water (H₂O).

D : Quick lime [CaO]

E : Downward displacement of air.

Question 4(2017)

Give a balanced chemical equation for each of the following —

(i) Catalytic oxidation of ammonia.

(ii) Reaction of ammonia with nitric acid.

Answer

(i) $4 NH_{3} + 5 O_{2} Pt.$

$800° C 4NO + 6H_{2} O + Δ$

(ii) NH₃ + HNO₃ ⟶ NH₄NO₃

Question 1(2018)

Write a balanced chemical equation — To prepare ammonia gas in the laboratory , by using an alkali.

Answer

2NH₄Cl + Ca(OH)₂ ⟶ CaCl₂ + 2H₂O + 2NH₃ [g]

Question 2(2018)

Give a reason why —

(i) Concentrated sulphuric acid, is not used for drying ammonia gas.

(ii) Ammonia gas is not collected over water.

Answer

(i) As sulphuric acid reacts chemically with ammonia to form ammonium sulphate hence, it is not used as a drying agent for drying ammonia.

2NH₃ + H₂SO₄ ⟶ (NH₄)₂SO₄

(ii) As ammonia gas is highly soluble in water hence, it is not collected over water.

Question 1(2019)

Fill in the blank with the choices given in the bracket: Ammonia reacts with excess chlorine to form ……………. [nitrogen / nitrogen trichloride / ammonium chloride]

Answer

Ammonia reacts with excess chlorine to form nitrogen trichloride

Question 2(2019)

State one observation for the following : Ammonia gas is passed over heated copper [II] oxide.

Answer

Black copper [II] oxide is reduced to brown copper.

2NH₃ + 3CuO ⟶ 3Cu + 3H₂O + N₂ [g]

Question 3(2019)

Identify the substance italicized : The catalyst used to oxidize ammonia.

Answer

Platinum

$4 NH_{3} + 5 O_{2} Pt.$

$800° C 4NO + 6H_{2} O + Δ$

Question 4(2019)

Name the gas evolved when : Ammonia reacts with heated copper [II] oxide.

Answer

Nitrogen

2NH₃ + 3CuO ⟶ 3Cu + 3H₂O + N₂ [g]

Question 5(2019)

Study the flowchart given and give balanced equations to represent the reactions A, B and C

$Mg_{3} N_{2} A$

$NH_{3} B$

$C NH_{4} Cl$

Answer

A : Mg₃N₂ + 6H₂O ⟶ 3Mg(OH)₂ + 2NH₃ [g]

B : NH₃ + HCl ⟶ NH₄Cl

C: NH₄Cl + NaOH ⟶ NaCl + H₂O + NH₃ [g]

Question 6(2019)

Copy and complete the following table which refers to the industrial method for preparation of ammonia.

Name of the compound	Name of the process	Catalytic equation [with the catalyst]
Ammonia

Answer

Name of the compound — Ammonia

Name of the process — Haber’s process

Catalytic equation [with the catalyst] — $N_{2} + 3 H_{2} Fe$

$450-500 °C 2NH_{3} + Δ$