STUDY OF COMPOUNDS - NH3

Detailed Study:

Part 1

Part 2

List of All Important Equations for NH3

Frequently Tested Topics:

  • Haber's process - equation, conditions, catalyst

  • Basic nature of ammonia

  • Preparation of ammonia from ammonium salts

  • Catalytic oxidation and burning of ammonia - equations and observations

  • Equations of chlorine with excess ammonia, and ammonia with excess chlorine

  • Precipitation reactions with ammonium hydroxide

*Note that other aspects of the chapter are equally important.

Important Past Questions:

  • Select the correct answer:

i) The compound which is not a metal hydroxide but its aqueous solution is alkaline in nature:

Ammonia, Copper oxide, Copper sulphate, Hydrogen chloride, Hydrogen sulphide, Lead bromide        (2006)

ii) A compound which on heating with NaOH produces a gas which forms dense white fumes with HCl:

Ammonium sulphate, Lead carbonate, Chlorine, Copper nitrate, Iron [II] sulphate

(2006)

iii) Ammonia can be obtained by adding water to:

A] Ammonium chloride B] Ammonium nitrite C] Magnesium nitride D] Magnesium nitrate

(2008)

iv) Nitrogen gas can be obtained by heating:

A] Ammonium nitrate B] Ammonium nitrite C] Magnesium nitrite D] Ammonium chloride

(2013)

v) Select the gas which is used as a reducing agent in reducing copper oxide to copper:

Ammonia, ethane, hydrogen chloride, hydrogen sulphide, ethyne

(2015)

  • Name:

i) The substance used for drying ammonia. (2006, 2012)

ii) The gas that burns in oxygen with a green flame. (2009)

iii) The gas produced when excess ammonia reacts with chlorine. (2012)

iv) An alkaline gas which produces dense white fumes when reacted with HCl gas. (2008, 2013)

v) The other ion formed when ammonia dissolves in water. Give one test that can be used to detect the presence of the ion produced. (2005, 2014)

  • State the observations when:

i) Excess ammonia is passed through an aq. solution of lead nitrate. (2006)

ii) In the absence of catalyst, ammonia is burned in an atmosphere of oxygen.  (2010, 2015, 2017)

iii) Ammonium hydroxide is first added in a small quantity and then in excess to a solution of copper sulphate. (2011)

iv) Water is added to the product formed, when Al is burnt in a jar of nitrogen gas. (2011)

v) Excess chlorine gas is reacted with ammonia gas. (2013)

vi) NH4OH soln. is added to zinc nitrate soln. slowly and then in excess. (2013)

vii) Calcium hydroxide is heated with ammonium chloride crystals. (2014)

  • Give reasons:

i) ammonium nitrate is not used in the preparation of ammonia. (2012)

ii) ammonia gas in not collected over water. (2012, 2018)

iii)  concentrated sulphuric acid, is not used for drying ammonia ages. (2018)

  • Give balanced chemical equations for:

i) A mixture of ammonium chloride and slaked lime is heated. (2005)

ii) Aluminium nitride reacts withe water. (2005, 2008, 2016)

iii) An equation to illustrate the reducing nature of ammonia. (2006, 2010, 2016)

iv)  Formation of ammonium sulphate from ammonia and dil. sulphuric acid. (2007, 2015)

v) Reaction in which NH3 is oxidized by 1) a metal oxide 2) a gas which is not oxygen (2007)

vi) Magnesium nitride is treated with warm water. (2009, 2014)

vii) Ammonium chloride is heated with sodium hydroxide. (2010, 2017, 2018)

viii) Chlorine reacts with excess of ammonia. (2011, 2016)

ix) Ammonia and oxygen in the presence of a catalyst. (2012, 2017)

x) Reduction of hot copper [II] oxide to copper using ammonia gas. (2013, 2017)

xi) Lab preparation of ammonia using ammonium salt. (2015)

xii) Reaction of ammonia with nitric acid (2017)

  • With reference to the manufacture of ammonia:

i) Write the equation and conditions required. (2006, 2010, 2013)

ii) Name the process. (2010)

iii) State the ratio of the reactants taken. (2010)

iv) State the catalyst used. (2010, 2013)

  • 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?

(2007)

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

Name of Process          Inputs                Catalyst               Equation for catalyzed reaction           Output

Haber's Process            Hydrogen +


(2008)

  • Identify the substance 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. 

(2009)

  • 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 solution, which will be b] ________ in nature, and will contain the ions c] _______ and d] _________. A e] ________ coloured precipitate of iron [II] hydroxide is formed when the above solution is added to iron [II] sulphate solution.

(2010)

  • Ammonia gas is collected by _________ [upward displacement of air, downward displacement of water, downward displacement of air]

(2014)

  • State the conditions required for catalytic oxidation of ammonia to nitric oxide.

(2014)

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

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

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

(2014)

  • Name the gas evolved when the following mixtures are heated:

i) calcium hydroxide and ammonium chloride

ii) sodium nitrite and ammonium chloride

(2016)

  • Give a reason why:

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

ii) Ammonia gas is not collected over water

(2018)

  • Certain blank spaces are left in the following table as C, D and E. Identify each.

Lab preparation of       Reactants used       Products formed    Drying agent        Method of collection

      NH3 gas                         C                   Mg(OH)2, NH3              D                                E