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    Laboratory Preparation of Ammonia

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    1. Experiment 13: LABORATORY PREPARATION OF AMMONIA GAS
    2. OBJECTIVE
    3. APPARATUS REQUIRED
    4. CHEMICALS REQUIRED
    5. THEORY
    6. PROCEDURE
    7. OBSERVATION TABLE
    8. Reactions involved
    9. RESULT
    10. CONCLUSION
    11. PRECAUTIONS

    Experiment 13: LABORATORY PREPARATION OF AMMONIA GAS

    OBJECTIVE

    LABORATORY PREPARATION OF AMMONIA GAS AND INVESTIGATING ITS PROPERTIES

    APPARATUS REQUIRED

    1. Round bottom flask
    2. Thistle funnel
    3. Delivery tube
    4. Cork
    5. Gas jars
    6. Test tube

    CHEMICALS REQUIRED

    1. Dilute HCl
    2. Ca(OH)2
    3. NaOH
    4. NH4Cl
    5. FeCl3
    6. CuSO4
    7. Litmus paper

    THEORY

    Ammonium salts treated with alkali give off ammonia gas. Ammonia gas is prepared in the laboratory by heating a paste of ammonium chloride and slaked lime. The gas is produced according to the following chemical reaction.

    Exp 13 rxn1
    Laboratory Preparation of Ammonia

    PROCEDURE

    A paste of ammonium chloride and dry-slaked lime was prepared by dissolving it in water. The paste was introduced in the round bottom flask. The apparatus was fitted as shown in the figure. The flask was clamped in a slightly inclined position. The flask was heated gently so that the reaction started and the gas was produced. Since the gas is highly soluble in water and lighter than air, it is collected in the gas jar by downward displacement of air.

    OBSERVATION TABLE

    ExperimentObservationInference
    1. The physical properties were noted:
    i. Colour
    ii. Odour
    iii. Solubility:
    The gas jar filled with
    NH3 gas was inverted over a water trough.    		1.
    i. No colour
    ii. Pungent odour
    iii. Water rises up in the jar.    		1. The gas is
    i. colourless
    ii. has a pungent odour
    iii. highly soluble in water.
    2. A burning candle was introduced into the gas jar full of NH3 gas2. The burning candle
    extinguished.    		2. NH3 gas is neither combustible nor the
    supporter of combustion.
    3. Moist blue litmus paper was brought in contact with NH3 gas.3. Red litmus paper turned blue.3. NH3 gas is basic.
    4. The gas filled in a round bottom flask was inverted over a water trough with a few drops of phenolphthalein.4. Water enters in the flask in the form of fountain and the solution turned pink.
    4. The gas is highly soluble and the solution
    is alkaline.
    5. The glass rod is moistened with
    HCl gas was brought near to
    ammonia gas.    		5. Dense white fumes were
    produced.
    5. Formation of fumes of NH4Cl.
    6. Ammonia gas was passed through copper sulphate solution.6. A blueish-white precipitate first formed which gets dissolved in excess NH3 and gives a deep blue solution.
    6. Initially cupric hydroxide was formed and then
    tetra amine copper
    sulphate was formed.
    7. Ammonia gas was passed through a ferric chloride solution.7. A brown precipitate was formed.7. Formation of ferric
    hydroxide

    Reactions involved

    1. Action with water

    NH_{3} +H_{2}O\rightleftharpoons NH_{4}OH  \rightleftharpoons  NH_{4}^{+}+OH^{-}

    5. Action with conc. HCl

    NH_{3} +HCl \rightarrow \underset{dense\ white\ fume}{NH_{4}Cl}

    6. Action with CuSO4 solution

    Exp 13 rxn2

    7. Action with FeCl3 solution

    Exp 13 rxn3

    RESULT

    Hence, ammonia gas was prepared and its properties were studied.

    CONCLUSION

    Hence, in this way, the gas is prepared in the laboratory and its properties are studied

    PRECAUTIONS

    1. The round bottom flask should be inclined.
    2. The cork should be fitted tightly.
    3. Heat should be gentle.

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