Selina Textbook Solutions: Study of Compounds - Ammonia | Chemistry Class 10 ICSE PDF Download

 Page 1


Class X Chapter 9 – Ammonia Chemistry 
_____________________________________________________________________________ 
 
EXERCISE 
 
Question 1:  
Draw a labelled diagram and give balanced equation for the lab. Preparation of ammonia. Also 
state physical properties of ammonia. 
Solution 1: 
Physical properties of ammonia are: 
Color : Colourless 
Odour : Strong, Pungent chocking smell 
Taste: Slightly bitter (alkaline ) taste 
Physiological action: Non-Poisonous 
Density: V.D = 8.5 Lighter than air 
Nature: Alkaline 
Liquefaction: easily liquefied at 10
o
C by compressing it at 6 atm. Pressure 
Boiling Point: Liquid ammonia boils at -33.5
o
C 
Freezing Point: Solid NH3 melts at -77.7
o
C 
Solubility: Highly soluble in water, 1vol of water dissolves about 702 vols. of ammonia at 20
o
C 
and 1 atm. pressure. 
Reaction : 
2NH4Cl + Ca(OH)2 ? CaCl2 + 2H2 + 2NH3 
 
 
Question 2:  
(a) Is ammonia more dense or less dense than air? 
(b) What property of ammonia is demonstrated by the fountain experiment? 
(c) Write the balanced equation for the reaction between ammonia and sulphuric acid. 
Solution 2: 
Ammonia is less dense than air. By Fountain Experiment we demonstrate the high solubility 
of ammonia gas in water. 
Balanced equation for the reaction between ammonia and sulphuric acid is: 
2NH3 + H2SO4 ? (NH4)2SO4 
 
Page 2


Class X Chapter 9 – Ammonia Chemistry 
_____________________________________________________________________________ 
 
EXERCISE 
 
Question 1:  
Draw a labelled diagram and give balanced equation for the lab. Preparation of ammonia. Also 
state physical properties of ammonia. 
Solution 1: 
Physical properties of ammonia are: 
Color : Colourless 
Odour : Strong, Pungent chocking smell 
Taste: Slightly bitter (alkaline ) taste 
Physiological action: Non-Poisonous 
Density: V.D = 8.5 Lighter than air 
Nature: Alkaline 
Liquefaction: easily liquefied at 10
o
C by compressing it at 6 atm. Pressure 
Boiling Point: Liquid ammonia boils at -33.5
o
C 
Freezing Point: Solid NH3 melts at -77.7
o
C 
Solubility: Highly soluble in water, 1vol of water dissolves about 702 vols. of ammonia at 20
o
C 
and 1 atm. pressure. 
Reaction : 
2NH4Cl + Ca(OH)2 ? CaCl2 + 2H2 + 2NH3 
 
 
Question 2:  
(a) Is ammonia more dense or less dense than air? 
(b) What property of ammonia is demonstrated by the fountain experiment? 
(c) Write the balanced equation for the reaction between ammonia and sulphuric acid. 
Solution 2: 
Ammonia is less dense than air. By Fountain Experiment we demonstrate the high solubility 
of ammonia gas in water. 
Balanced equation for the reaction between ammonia and sulphuric acid is: 
2NH3 + H2SO4 ? (NH4)2SO4 
 
Class X Chapter 9 – Ammonia Chemistry 
_____________________________________________________________________________ 
 
 
Question 3:  
Pick the odd member from the list giving reasons: 
(a) Ammonia, sulphur dioxide, hydrogen chloride, carbon dioxide. 
(b) Copper oxide, aluminium oxide, sodium oxide, magnesium oxide. 
Solution 3: 
(a) Ammonia is basic in nature. 
(b) Copper oxide because CuO is less reactive can be reduced by C, CO or by hydrogen whereas 
Al2O3, Na2O, MgO are reduced by electrolysis. 
 
 
Question 4:  
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? 
Solution 4: 
(a) The formula of the compound is 
32
Mg N
. 
(b) Balanced equation : 
32
Mg N + 6 H2O ?3 Mg(OH)2 + 2 NH3 
(c) Ammonia is a reducing agent and reduces less active metal oxide to its respective metal. 
 
 
Question 5:  
Ammonium salts decompose on heating. What other property do ammonium salts have in 
common? 
Solution 5: 
Reducing property. 
 
 
Page 3


Class X Chapter 9 – Ammonia Chemistry 
_____________________________________________________________________________ 
 
EXERCISE 
 
Question 1:  
Draw a labelled diagram and give balanced equation for the lab. Preparation of ammonia. Also 
state physical properties of ammonia. 
Solution 1: 
Physical properties of ammonia are: 
Color : Colourless 
Odour : Strong, Pungent chocking smell 
Taste: Slightly bitter (alkaline ) taste 
Physiological action: Non-Poisonous 
Density: V.D = 8.5 Lighter than air 
Nature: Alkaline 
Liquefaction: easily liquefied at 10
o
C by compressing it at 6 atm. Pressure 
Boiling Point: Liquid ammonia boils at -33.5
o
C 
Freezing Point: Solid NH3 melts at -77.7
o
C 
Solubility: Highly soluble in water, 1vol of water dissolves about 702 vols. of ammonia at 20
o
C 
and 1 atm. pressure. 
Reaction : 
2NH4Cl + Ca(OH)2 ? CaCl2 + 2H2 + 2NH3 
 
 
Question 2:  
(a) Is ammonia more dense or less dense than air? 
(b) What property of ammonia is demonstrated by the fountain experiment? 
(c) Write the balanced equation for the reaction between ammonia and sulphuric acid. 
Solution 2: 
Ammonia is less dense than air. By Fountain Experiment we demonstrate the high solubility 
of ammonia gas in water. 
Balanced equation for the reaction between ammonia and sulphuric acid is: 
2NH3 + H2SO4 ? (NH4)2SO4 
 
Class X Chapter 9 – Ammonia Chemistry 
_____________________________________________________________________________ 
 
 
Question 3:  
Pick the odd member from the list giving reasons: 
(a) Ammonia, sulphur dioxide, hydrogen chloride, carbon dioxide. 
(b) Copper oxide, aluminium oxide, sodium oxide, magnesium oxide. 
Solution 3: 
(a) Ammonia is basic in nature. 
(b) Copper oxide because CuO is less reactive can be reduced by C, CO or by hydrogen whereas 
Al2O3, Na2O, MgO are reduced by electrolysis. 
 
 
Question 4:  
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? 
Solution 4: 
(a) The formula of the compound is 
32
Mg N
. 
(b) Balanced equation : 
32
Mg N + 6 H2O ?3 Mg(OH)2 + 2 NH3 
(c) Ammonia is a reducing agent and reduces less active metal oxide to its respective metal. 
 
 
Question 5:  
Ammonium salts decompose on heating. What other property do ammonium salts have in 
common? 
Solution 5: 
Reducing property. 
 
 
Class X Chapter 9 – Ammonia Chemistry 
_____________________________________________________________________________ 
 
Question 6:  
State what you observe when a piece of moist red litmus paper is placed in a gas jar of 
ammonia. 
Solution 6: 
When a piece of moist red litmus paper is placed in a gas jar of ammonia it turns blue. 
 
 
Question 7:  
A gas ‘P’ gives dense white fumes with chlorine. Its aqueous solution gives a blue colour with 
copper (II) hydroxide  (a) Name the gas P. (b) Give its formula (c) Give three uses of P. 
Solution 7: 
(a) The gas is ammonia. 
(b) The formula is NH3. 
(c) Uses of ammonia: 
It is used in the industrial preparation of nitric acid by Ostwald process. 
It is used in the manufacture of fertilizers such as ammonium sulphate, ammonium nitrate, 
ammonium phosphate. 
It is used in the manufacture sodium carbonate by Solvay process. 
NaCl + NH3 + CO2 + H2O ?NaHCO3 +NH4Cl 
 
 
Question 8:  
Ammonia solution in water gives a blue precipitate when it combines with a solution of copper 
salt. The blue precipitate further dissolves in excess of ammonia solution to give azure blue 
solution. Explain with equation. 
Solution 8: 
Equation: 
CuSO4 +2NH4OH ? ? ? Cu(OH)2 ? + [NH4]2SO4 
pale blue 
Ammonia solution in water gives a blue precipitate when it combines with a solution of copper 
salt. 
The pale blue precipitate of copper hydroxide dissolves in excess of ammonium hydroxide 
forming tetraamine copper[II] sulphate, an azure blue (deep blue)soluble complex salt. 
Cu(OH)2 +(NH4)2SO4 +2NH4OH ? [Cu(NH3)4]SO4 + 4H2O 
 
 
Page 4


Class X Chapter 9 – Ammonia Chemistry 
_____________________________________________________________________________ 
 
EXERCISE 
 
Question 1:  
Draw a labelled diagram and give balanced equation for the lab. Preparation of ammonia. Also 
state physical properties of ammonia. 
Solution 1: 
Physical properties of ammonia are: 
Color : Colourless 
Odour : Strong, Pungent chocking smell 
Taste: Slightly bitter (alkaline ) taste 
Physiological action: Non-Poisonous 
Density: V.D = 8.5 Lighter than air 
Nature: Alkaline 
Liquefaction: easily liquefied at 10
o
C by compressing it at 6 atm. Pressure 
Boiling Point: Liquid ammonia boils at -33.5
o
C 
Freezing Point: Solid NH3 melts at -77.7
o
C 
Solubility: Highly soluble in water, 1vol of water dissolves about 702 vols. of ammonia at 20
o
C 
and 1 atm. pressure. 
Reaction : 
2NH4Cl + Ca(OH)2 ? CaCl2 + 2H2 + 2NH3 
 
 
Question 2:  
(a) Is ammonia more dense or less dense than air? 
(b) What property of ammonia is demonstrated by the fountain experiment? 
(c) Write the balanced equation for the reaction between ammonia and sulphuric acid. 
Solution 2: 
Ammonia is less dense than air. By Fountain Experiment we demonstrate the high solubility 
of ammonia gas in water. 
Balanced equation for the reaction between ammonia and sulphuric acid is: 
2NH3 + H2SO4 ? (NH4)2SO4 
 
Class X Chapter 9 – Ammonia Chemistry 
_____________________________________________________________________________ 
 
 
Question 3:  
Pick the odd member from the list giving reasons: 
(a) Ammonia, sulphur dioxide, hydrogen chloride, carbon dioxide. 
(b) Copper oxide, aluminium oxide, sodium oxide, magnesium oxide. 
Solution 3: 
(a) Ammonia is basic in nature. 
(b) Copper oxide because CuO is less reactive can be reduced by C, CO or by hydrogen whereas 
Al2O3, Na2O, MgO are reduced by electrolysis. 
 
 
Question 4:  
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? 
Solution 4: 
(a) The formula of the compound is 
32
Mg N
. 
(b) Balanced equation : 
32
Mg N + 6 H2O ?3 Mg(OH)2 + 2 NH3 
(c) Ammonia is a reducing agent and reduces less active metal oxide to its respective metal. 
 
 
Question 5:  
Ammonium salts decompose on heating. What other property do ammonium salts have in 
common? 
Solution 5: 
Reducing property. 
 
 
Class X Chapter 9 – Ammonia Chemistry 
_____________________________________________________________________________ 
 
Question 6:  
State what you observe when a piece of moist red litmus paper is placed in a gas jar of 
ammonia. 
Solution 6: 
When a piece of moist red litmus paper is placed in a gas jar of ammonia it turns blue. 
 
 
Question 7:  
A gas ‘P’ gives dense white fumes with chlorine. Its aqueous solution gives a blue colour with 
copper (II) hydroxide  (a) Name the gas P. (b) Give its formula (c) Give three uses of P. 
Solution 7: 
(a) The gas is ammonia. 
(b) The formula is NH3. 
(c) Uses of ammonia: 
It is used in the industrial preparation of nitric acid by Ostwald process. 
It is used in the manufacture of fertilizers such as ammonium sulphate, ammonium nitrate, 
ammonium phosphate. 
It is used in the manufacture sodium carbonate by Solvay process. 
NaCl + NH3 + CO2 + H2O ?NaHCO3 +NH4Cl 
 
 
Question 8:  
Ammonia solution in water gives a blue precipitate when it combines with a solution of copper 
salt. The blue precipitate further dissolves in excess of ammonia solution to give azure blue 
solution. Explain with equation. 
Solution 8: 
Equation: 
CuSO4 +2NH4OH ? ? ? Cu(OH)2 ? + [NH4]2SO4 
pale blue 
Ammonia solution in water gives a blue precipitate when it combines with a solution of copper 
salt. 
The pale blue precipitate of copper hydroxide dissolves in excess of ammonium hydroxide 
forming tetraamine copper[II] sulphate, an azure blue (deep blue)soluble complex salt. 
Cu(OH)2 +(NH4)2SO4 +2NH4OH ? [Cu(NH3)4]SO4 + 4H2O 
 
 
Class X Chapter 9 – Ammonia Chemistry 
_____________________________________________________________________________ 
 
Question 9:  
How do you prove that NH3 contains nitrogen and hydrogen? 
Solution 9: 
Ammonia dissociates into nitrogen and hydrogen at high temperature or by electric sparks. 
2
N
32
2NH 3H ? 
 
 
Question 10:  
Give reasons for the following: 
(a) Liquid ammonia is used as a refrigerant in ice plants. 
(b)  Aqueous solution of ammonia is used for removing grease stains from woolen clothes  
(c) Aqueous solution of ammonia gives a pungent smell 
(d) Aqueous solution of ammonia conducts electricity  
Solution 10: 
(a) Liquid ammonia takes a lot of energy to vaporize. This heat is taken from the surrounding 
bodies which are consequently cooled down. Thus it is used as a refrigerant in ice plant. 
(b) Ammonia emulsifies or dissolves fats, grease so it is used to remove grease from woolen 
clothes. 
(c) Aqueous solution of ammonia gives pungent smell because of the presence of ammonia. 
(d) Aqueous ammonia when dissolved in water breaks into ions which help in the conductance 
of electricity. 
       NH3 + H2O ? NH4OH  NH4
+
 + OH
- 
 
 
Question 11:  
Copy and complete the following equations. 
(a) AIN + H2O ? 
(b) 2NH3 + 3PbO ? 
(c) NH3 + 3CI2 ? 
(d) NH3 + CO2 
? 
(i) which property of ammonia is illustrated by equation (c) ? 
(ii) what important fertilizer is prepared from equation (d) ? 
Solution 11: 
(a) AlN + 3H2O ? Al(OH)3 + NH3 
(b) 2NH3 + 3PbO ? 3Pb + 3H2O + N2 
(c) 8NH3 + 3Cl2 ? N2 + 6NH4Cl 
(d) 2NH3 + CO2 ? NH2CONH2 + H2O 
(i) Ammonia act as reducing agent is explained by equation (c). 
(ii) Urea the nitrogenous fertilizer is prepared from equation (d). 
 
Page 5


Class X Chapter 9 – Ammonia Chemistry 
_____________________________________________________________________________ 
 
EXERCISE 
 
Question 1:  
Draw a labelled diagram and give balanced equation for the lab. Preparation of ammonia. Also 
state physical properties of ammonia. 
Solution 1: 
Physical properties of ammonia are: 
Color : Colourless 
Odour : Strong, Pungent chocking smell 
Taste: Slightly bitter (alkaline ) taste 
Physiological action: Non-Poisonous 
Density: V.D = 8.5 Lighter than air 
Nature: Alkaline 
Liquefaction: easily liquefied at 10
o
C by compressing it at 6 atm. Pressure 
Boiling Point: Liquid ammonia boils at -33.5
o
C 
Freezing Point: Solid NH3 melts at -77.7
o
C 
Solubility: Highly soluble in water, 1vol of water dissolves about 702 vols. of ammonia at 20
o
C 
and 1 atm. pressure. 
Reaction : 
2NH4Cl + Ca(OH)2 ? CaCl2 + 2H2 + 2NH3 
 
 
Question 2:  
(a) Is ammonia more dense or less dense than air? 
(b) What property of ammonia is demonstrated by the fountain experiment? 
(c) Write the balanced equation for the reaction between ammonia and sulphuric acid. 
Solution 2: 
Ammonia is less dense than air. By Fountain Experiment we demonstrate the high solubility 
of ammonia gas in water. 
Balanced equation for the reaction between ammonia and sulphuric acid is: 
2NH3 + H2SO4 ? (NH4)2SO4 
 
Class X Chapter 9 – Ammonia Chemistry 
_____________________________________________________________________________ 
 
 
Question 3:  
Pick the odd member from the list giving reasons: 
(a) Ammonia, sulphur dioxide, hydrogen chloride, carbon dioxide. 
(b) Copper oxide, aluminium oxide, sodium oxide, magnesium oxide. 
Solution 3: 
(a) Ammonia is basic in nature. 
(b) Copper oxide because CuO is less reactive can be reduced by C, CO or by hydrogen whereas 
Al2O3, Na2O, MgO are reduced by electrolysis. 
 
 
Question 4:  
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? 
Solution 4: 
(a) The formula of the compound is 
32
Mg N
. 
(b) Balanced equation : 
32
Mg N + 6 H2O ?3 Mg(OH)2 + 2 NH3 
(c) Ammonia is a reducing agent and reduces less active metal oxide to its respective metal. 
 
 
Question 5:  
Ammonium salts decompose on heating. What other property do ammonium salts have in 
common? 
Solution 5: 
Reducing property. 
 
 
Class X Chapter 9 – Ammonia Chemistry 
_____________________________________________________________________________ 
 
Question 6:  
State what you observe when a piece of moist red litmus paper is placed in a gas jar of 
ammonia. 
Solution 6: 
When a piece of moist red litmus paper is placed in a gas jar of ammonia it turns blue. 
 
 
Question 7:  
A gas ‘P’ gives dense white fumes with chlorine. Its aqueous solution gives a blue colour with 
copper (II) hydroxide  (a) Name the gas P. (b) Give its formula (c) Give three uses of P. 
Solution 7: 
(a) The gas is ammonia. 
(b) The formula is NH3. 
(c) Uses of ammonia: 
It is used in the industrial preparation of nitric acid by Ostwald process. 
It is used in the manufacture of fertilizers such as ammonium sulphate, ammonium nitrate, 
ammonium phosphate. 
It is used in the manufacture sodium carbonate by Solvay process. 
NaCl + NH3 + CO2 + H2O ?NaHCO3 +NH4Cl 
 
 
Question 8:  
Ammonia solution in water gives a blue precipitate when it combines with a solution of copper 
salt. The blue precipitate further dissolves in excess of ammonia solution to give azure blue 
solution. Explain with equation. 
Solution 8: 
Equation: 
CuSO4 +2NH4OH ? ? ? Cu(OH)2 ? + [NH4]2SO4 
pale blue 
Ammonia solution in water gives a blue precipitate when it combines with a solution of copper 
salt. 
The pale blue precipitate of copper hydroxide dissolves in excess of ammonium hydroxide 
forming tetraamine copper[II] sulphate, an azure blue (deep blue)soluble complex salt. 
Cu(OH)2 +(NH4)2SO4 +2NH4OH ? [Cu(NH3)4]SO4 + 4H2O 
 
 
Class X Chapter 9 – Ammonia Chemistry 
_____________________________________________________________________________ 
 
Question 9:  
How do you prove that NH3 contains nitrogen and hydrogen? 
Solution 9: 
Ammonia dissociates into nitrogen and hydrogen at high temperature or by electric sparks. 
2
N
32
2NH 3H ? 
 
 
Question 10:  
Give reasons for the following: 
(a) Liquid ammonia is used as a refrigerant in ice plants. 
(b)  Aqueous solution of ammonia is used for removing grease stains from woolen clothes  
(c) Aqueous solution of ammonia gives a pungent smell 
(d) Aqueous solution of ammonia conducts electricity  
Solution 10: 
(a) Liquid ammonia takes a lot of energy to vaporize. This heat is taken from the surrounding 
bodies which are consequently cooled down. Thus it is used as a refrigerant in ice plant. 
(b) Ammonia emulsifies or dissolves fats, grease so it is used to remove grease from woolen 
clothes. 
(c) Aqueous solution of ammonia gives pungent smell because of the presence of ammonia. 
(d) Aqueous ammonia when dissolved in water breaks into ions which help in the conductance 
of electricity. 
       NH3 + H2O ? NH4OH  NH4
+
 + OH
- 
 
 
Question 11:  
Copy and complete the following equations. 
(a) AIN + H2O ? 
(b) 2NH3 + 3PbO ? 
(c) NH3 + 3CI2 ? 
(d) NH3 + CO2 
? 
(i) which property of ammonia is illustrated by equation (c) ? 
(ii) what important fertilizer is prepared from equation (d) ? 
Solution 11: 
(a) AlN + 3H2O ? Al(OH)3 + NH3 
(b) 2NH3 + 3PbO ? 3Pb + 3H2O + N2 
(c) 8NH3 + 3Cl2 ? N2 + 6NH4Cl 
(d) 2NH3 + CO2 ? NH2CONH2 + H2O 
(i) Ammonia act as reducing agent is explained by equation (c). 
(ii) Urea the nitrogenous fertilizer is prepared from equation (d). 
 
Class X Chapter 9 – Ammonia Chemistry 
_____________________________________________________________________________ 
 
Question 12:  
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 Haber process  
(d) Conc. H2SO4 is a drying agent for NH3 
(e) Ammonium salts, on heating, decompose to give ammonia. 
Solution 12: 
(a) A Dirty green precipitate of Fe(OH)2 is obtained when ammonium hydroxide is added to 
ferrous sulphate. 
(b) Liquid ammonia is liquefied ammonia. 
(c) Finely divided Iron is used in Haber process. 
(d) Quicklime is a drying agent for NH3. 
(e) Ammonium salts when heated with caustic alkali. 
 
 
Question 13:  
What do you observe when ammonium hydroxide is added to the aqueous solution of: 
(a) FeSO4        (b) Iron (III) chloride,      (c) Lead nitrate     (d) Zinc nitrate? 
Solution 13: 
(a) Dirty green ppt. of Ferrous hydroxide is formed which is insoluble in excess of NH4OH. 
      FeSO4 + 2NH4OH ? [NH4]2SO4 + Fe(OH)2 
(b) Reddish brown ppt. of ferric hydroxide is formed which is insoluble in ammonium  
       hydroxide. 
      FeCl3 + 3NH4OH ? 3NH4Cl + Fe(OH)3 
(c) White ppt. of lead hydroxide is formed which is insoluble in NH4OH. 
       Pb(NO3)2 + 2NH4OH ? 2NH4NO3 + Pb(OH)2 
(d) White gelatinous ppt. of Zinc hydroxide is formed which is soluble in NH4OH. 
      Zn(NO3)2 + 2NH4OH ? 2NH4NO3 + Zn(OH)2 
 
 
Question 14:  
Why is ammonium hydroxide used in qualitative analysis? Give two equations to justify your 
answer 
Solution 14: 
When correct amount of ammonium hydroxide is added drop wise to solutions of the metallic 
salts, ppts. (coloured generally) are formed. They help us to identify their metal ions. 
Two equations: 
FeSO4 + 2NH4OH ? (NH4).2SO4 +  Fe (OH)2