Question

Ammonia gas is collected by _______.
(an upward displacement of air, a downward displacement of water, a downward displacement of air)

Answer 1

Ammonia is a compound of nitrogen and Hydrogen with formula $N{H_3}.$This is colorless gas with a pungent smell. It is lighter than air.

Complete step by step answer:
Ammonia gas manufactured by Habei’s process. The reaction is as follows:
${N_{2(g)}} + 3{H_{2(g)}}\underset {} \leftrightarrows 2N{H_{3(g)}}$
$\Delta H = - 92kJ/mol$
In order to get more ammonia, the temperature should be low and pressure should be high. The catalyst does not have any effect on production of ammonia.
In Laboratory ammonium gas is prepared by slowly heating ammonium chloride $(N{H_3}Cl)$and slaked time $[Ca{(OH)_2}].$
$2N{H_4}Cl + Ca{(OH)_2} \to CaC{l_2} + {H_2}O + 2N{H_3} \uparrow$
Since ammonia gas is lighter than air therefore it is collected by downward displacement of air.
Ammonia is soluble in water therefore cannot be collected over it.

So, the correct answer is “Option C”.

Additional Information:
Ammonia is stable binary hydride Binary hydride means a compound containing atoms of two different elements out of which one is hydrogen.
It is a colorless gas and pungent smell.
Its molecular mass is $17.031g/mol.$
Ammonia gas is used as refrigerant gas manufacture of plastic, textiles, pesticides dyes and other chemicals.
The odor of ammonia is familiar to many people because it is commonly used in cleaning products and smelling salts.

Note:
The density of ammonia is $0.589$ times that of air. So it is lighter than air.
It is easily liquefied due to strong hydrogen bonding.
Ammonia gas is produced naturally in the human body and in nature, in water, soil and air.