Question

$NH_4Cl(s)$ 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 $NH_4OH$ and $HCl$
• B. formation of $NH_3$ and $HCl$
• C. greater diffusion of $NH_3$ than $HCl$
• D. greater diffusion of $HCl$ than $NH_3$

Answer 1

Answer: (C)

greater diffusion of $NH_3$ than $HCl$

Answer 2

${NH4Cl(s) ->[{\Delta}][{}] NH_3}$ ${ - ^ +HCI (^)}$ Graham?? law of diffusion says, lighter gas will diffuse most rapidly. Therefore, $NH_3$ will be (mol. wt. $= 17$) diffused rapidly than $HCl$. (mol. wt. $= 36.5$).