Ammonia
Q1. Choose the correct option.
(i) An aqueous solution of ammonia is: [1][2022]
a.
Neutral
b.
Acidic
c.
Basic
d.
Amphoteric
Show Answer
Ans. c. Basic
(ii) The catalyst used in the Haber’s Process is: [1][Specimen
2023]
a.
Molybdenum
b.
Platinum
c.
Nickel
d. Finely divided iron
Show Answer
Ans. d. Finely divided iron
(iii) Nitrogen gas can be obtained by
heating: [2013][1]
a. Ammonium nitrate
b. Ammonium nitrite
c. Magnesium nitride
d. Ammonium chloride
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Ans. b. Ammonium nitrite
Q2. Name the gas in each of the following:
(i) The gas produced when excess ammonia reacts with
chlorine. [1][2012]
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Ans. Nitrogen
(ii) This gas is used as a reducing agent in reducing copper oxide to copper. [1][2015]
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Ans. Ammonia
(iii) The gas evolved when ammonia reacts with heated copper oxide. [1][2019]
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Ans. Nitrogen (N2)
Q3. Write balanced chemical equations for the following:
(i) Chlorine reacts with excess of ammonia. [1][2011][2016][2020]
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Ans. 8NH3 + 3Cl2 ---------> N2 + 6NH4Cl
(ii) Reduction of hot copper (II) oxide to copper using ammonia gas. [1][2013]
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Ans. 2NH3 + 3CuO ------> 3Cu + 3H2O + N2↑
(iii) Action of warm water on magnesium nitride. [1][2014]
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Ans. Mg3N2 + 6H2O --------> 3Mg(OH)2 + 2NH3↑
(iv) Lab preparation of ammonia using an ammonium salt. [1][2015]
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Ans. 2NH4Cl + Ca(OH)2 --------> CaCl2 + 2H2O + 2NH3↑
(v) Reaction of ammonia with excess chlorine. [1][2015]
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Ans. NH3 + 3Cl2 --------> 3HCl + NCl3
(vi) Reaction of ammonia with sulphuric acid. [1][2015]
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Ans. 2NH3 + H2SO4 -------> (NH4)2SO4
(vii) Action of warm water on AlN. [1][2016]
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Ans. AlN + 3H2O ---------> Al(OH)3 + NH3↑
(viii) An equation to illustrate the reducing nature of ammonia. [1][2016]
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Ans. 2NH3 + 3CuO ------> 3Cu + 3H2O + N2↑
(ix) Reaction of ammonia with heated copper oxide. [1][2017]
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Ans. 2NH3 + 3CuO ------> 3Cu + 3H2O + N2↑
(x) Laboratory preparation of ammonia from ammonium chloride. [1][2017][2018]
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Ans. 2NH4Cl + Ca(OH)2 --------> CaCl2 + 2H2O + 2NH3↑
(xi) Catalytic oxidation of ammonia. [1][2017]
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Ans. 4NH3 + 5O2 ----Pt 700-800°C----> 4NO + 6H2O + heat
(xii) Formation of ammonium sulphate from ammonium hydroxide and sulphuric acid. [1][2022]
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Q4. What would you observe in each of the following cases?
(i) Water is added to the product formed, when aluminium is burnt in a jar of nitrogen gas. [1][2011]
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Ans. A colourless gas with characteristic pungent smell of ammonia is formed.
(ii) Excess of chlorine gas is reacted with ammonia gas. [1][2013][2022]
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Ans. Yellow coloured highly explosive liquid nitrogen trichloride is formed.
(iii) When calcium hydroxide is heated with ammonium chloride crystals. [1][2014]
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Ans. A colourless gas with characteristic pungent smell of ammonia is evolved.
(iv) When ammonia gas is burnt in an atmosphere of excess oxygen. [1][2015]
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Ans. Ammonia burns with a greenish yellow flame.
(v) Burning of ammonia in air. [1][2017]
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Ans. Ammonia burns with a greenish yellow flame.
(vi) Ammonia gas is passed over heated copper (II) oxide. [1][2019]
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Ans. The black copper oxide is reduced to reddish brown copper.
(vii) Dry ammonia gas reacts with oxygen in the presence of a catalyst. [1][2022]
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Ans. Reddish brown vapours of nitrogen dioxide are formed.
Q5. Fill in the blanks from the choices given within brackets:
(i) Ammonia gas is collected by ……………… (an upward displacement of air, a downward displacement of water, a downward displacement of air). [1][2014]
Show Answer
Ans. a downward displacement of air
(ii) Ammonia reacts with excess chlorine to form …………. (nitrogen/nitrogen trichloride/ammonium chloride) [1][2019]
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Ans. nitrogen trichloride
(iii) Ammonia in the liquefied form is _________. [neutral/basic] [1][Specimen 2023]
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Ans. neutral
(iv) An alkaline gas gives dense white fumes of ________. [NH4OH/NH4Cl] with hydrogen chloride gas. [1][Specimen 2023]
Show Answer
Ans. NH4Cl
Q6. Identify the following substances which are underlined:
(i) An alkaline gas which produces dense white fumes when reacted with hydrogen chloride gas. [1][2013]
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Ans. ammonia
(ii) A solid formed by reaction of two gases, one of which is acidic and the other basic in nature. [1][2017]
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Ans. Ammonium chloride
(iii) The catalyst used to oxidise ammonia. [1][2019]
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Ans. Platinum
Q7. The diagram shows an experimental set up for the
laboratory preparation of a pungent smelling gas. The gas is alkaline in
nature. [5][2011][Specimen 2023]
(i) Name the gas collected in the jar.
(ii) Write the balanced equation for the above preparation.
(iii) How is the gas being collected?
(iv) Name the drying agent used.
(v) How will you find that the jar is full of gas?
Show Answer
Ans.
(i) Ammonia
(ii) Ca(OH)2 + 2NH4Cl -------heat-----> CaCl2 + 2H2O + 2NH3
(iii) Downward displacement of air
(iv) Quicklime (CaO)
(v) By bringing a rod dipped in hydrochloric acid near the mouth of the gas jar. When jar is full, dense white fumes of NH4Cl will be formed.
Q8. The following questions are based on the preparation
of ammonia gas in the laboratory: [4][2012]
(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?
(iv) Explain why it is not collected over water? [2018]
Show Answer
Ans.
(i) Because it is explosive in nature and decomposes into Nitrous oxide and water on heating.
(ii) Quick lime (CaO)
(iii) Downward displacement of air
(iv) Because it is highly soluble in water.
Q9. Some word/words are missing in the following
statements. You are required to rewrite the statements in the correct form using
the appropriate word/words.
(i) Magnesium nitride reacts with water to liberate ammonia.
[1][2012]
Show Answer
Ans. Magnesium nitride reacts with warm water to liberate ammonia.
Q10. [2014][2]
(i) Name the other ion formed when ammonia dissolves in water.
Show Answer
Ans. Hydroxide ion
(ii) Give one test that can be used to detect the presence of the ion produced.
Show Answer
Ans. It will turn moist red litmus paper to blue.
Q11. Name the gas evolved when the following mixtures are
heated: [2][2016]
(i) Calcium hydroxide and ammonium chloride.
Show Answer
Ans. Ammonia
(ii) Sodium nitrite and ammonium chloride.
Show Answer
Ans. Nitrogen
Q12. Certain blank spaces are left in the following table
and these are labelled as C, D and E. Identify each of them: [3][2017]
|
Laboratory
preparation of |
Reactants
used |
Products
formed |
Drying
agent |
Method
of collection |
|
NH3
gas |
C |
Mg(OH)2 + NH3 |
D |
E |
Show Answer
Ans.
C. Mg3N2 + H2O
D. CaO
E. Downward displacement of air.
Q13. State why concentrated sulphuric acid is not used for
drying ammonia gas. [1][2018]
Show Answer
Ans. Because concentrated sulphuric acid being acidic in nature, reacts with basic ammonia gas to give ammonium sulphate.
Q14. Study the flow chart given and give balanced equations
to represent the reactions A, B and C: [3][2019]
Show Answer
Ans.
A. Mg3N2 + 6H2O --------> 3Mg(OH)2 + 2NH3↑
B. NH3 + HCl -------> NH4Cl
C. Ca(OH)2 + 2NH4Cl -------heat-----> CaCl2 + 2H2O + 2NH3↑
Q15. Copy and complete the following table which refers to
the industrial method for the preparation of ammonia. [2][2019]
|
Name
of the compound |
Name
of the process |
Catalytic
equation (with the catalyst) |
|
Ammonia |
(i) …………………………….. |
(ii) …………………………. |
Show Answer
Ans.
Name of the compound | Name of the process | Catalytic equation (with the catalyst) |
Ammonia | (i) Haber’s process | (ii) N2 + 3H2 (finely divided iron)⇋2NH3 |
Q16. State the following:
A compound formed when excess ammonia gas reacts with chlorine. [1][2022]
Show Answer
Ans. Ammonium chloride
Q17. Complete the table given below which refers to the
Laboratory preparation of ammonia gas: [3][2022]
|
Laboratory
preparation |
Reactants
used |
Products
formed |
Drying
agent |
Method
of collection |
|
Ammonia
gas |
(a) ………….. |
Calcium
chloride + water + ammonia |
(b) ………………. |
(c) …………….. |
Show Answer
Ans.
a. Ammonium chloride + Calcium hydroxide
b. Quicklime (CaO)
c. Downward displacement of air
Q18. State one property of ammonia demonstrated in the
Fountain experiment. [1][Specimen 2023]
Show Answer
Ans. It is highly soluble in water.
Q19. Give the ionic equation when ammonium hydroxide is
dissolved in water. [1][Specimen 2023]
Show Answer
Ans. NH4OH ⇋NH4+ + OH-
Q20. State the conditions required for the conversion of
nitrogen to ammonia. [1][Specimen 2023]
Show Answer
Ans.
Temperature: 450-500°C
Pressure: Above 200 atm
Catalyst: Finely divided iron
Promoter: Traces of molybdenum
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