Question

$N{H}_{4}Cl\left(s\right)$ is heated in a test tube. Vapours are brought in contact with red litmus paper, which changes it to blue and then to red. It is because of :

• A. formation of $N{H}_{4}OH$ and $HCl$
• B. formation of $N{H}_3$ and $HCl$
• C. greater diffusion of $N{H}_3$ than $HCl$
• D. greater diffusion of $HCl$ than $N{H}_3$

Answer 1

The correct option is C greater diffusion of $N{H}_3$ than $HCl$

$N{H}_{4}Cl\left(s\right)\stackrel{\Delta }{\to }N{H}_3\uparrow +HCl\uparrow$

Graham's law of diffusion says, lighter gas will diffuse most rapidly. Therefore, $N{H}_3$ will be (mol. wt. $=17$) diffused rapidly than $HCl$ (mol. wt. $=36.5$).