Question

The statements regarding preparations of ammonia is/are :
(i) Raw materials in cyanamide process are limestone, coke and nitrogen gas.
(ii) On heating nitrogen gas and $Ca(OH{)}_2$, $N{H}_3$ is formed.
(iii) In Haber's process 100% yield of $N{H}_3$ is possible at ${500}^{o}C$ and 250 atm.

• A. all are correct
• B. i and ii
• C. i
• D. i and iii

Answer 1

Answer: (C)

i

(i) The essential materials for the manufacture of calcium cyanamide are limestone, carbon, and nitrogen. The production of calcium carbide is effected by first burning the limestone ($CaC{O}_3$) to lime ($CaO$) and then fusing of the lime with carbon (anthracite coal, or coke) in an electric furnace.
$CaC{O}_3\to CaO+C{O}_2$
$CaO+3C\to Ca{C}_2+CO$
The direct fixation of nitrogen is brought about by heating the powdered calcium carbide in an atmosphere of nitrogen:.
$Ca{C}_2+N_2\to CaNCN+C$.

(ii) Ammonia is prepared in laboratory by heating $N{H}_{4}Cl$ with slaked lime $Ca{\left(OH\right)}_2$ in the ratio of 3:2.

(iii) In Haber's process, at ${200}^{o}C$ and pressures above 750 atm there is an almost 100% conversion of reactants to the ammonia product is possible.

So, only statement i is correct.