Explanation

(c)
Dalton’s law of partial pressure : This law states that the total pressure exerted by a mixture of non-reacting gases is equal to the sum of partial pressure exerted by the individual gases.
$p = p_{1} + p_{2} + p_{3}\ldots$
Dalton’s law of partial pressure follows by the mixture of non-reacting gas but ${NH}_{3}$ react with HCl gives ${NH}_{4}Cl.$
${NH}_{3} + HCl\ \rightarrow {NH}_{4}Cl$
Hence, Dalton’s law of partial pressure is not applicable to ${NH}_{3} + HCl.$