Question

Explain why?

White thick fumes are formed when a glass rod dipped in ${\text{NH}}_{\text{4}}\text{OH}$ is brought near the mouth of a bottle full of $\text{HCl}$ gas.

Answer 1

1. When a glass rod dipped in Ammonia hydroxide is brought near the mouth of a bottle full of $\mathrm{HCl}$ gas, thick white fumes arise because ${\mathrm{NH}}_4\mathrm{OH}$ precipitation occurs, resulting in white fumes.
2. The production of Ammonium chloride, which contains Ammonium cation and Chloride ion as an anion, produces white emissions.

$$\begin{gathered} {\mathrm{NH}}_4\mathrm{OH}\left(\mathrm{liq}\right)+\mathrm{HCI}\left(\mathrm{aq}\right)\to {\mathrm{NH}}_4\mathrm{CI}\left(\mathrm{aq}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{liq}\right) \\ \text{(Ammonium hydroxide) (Hydrogen chloride) (Ammonium Chloride)} \end{gathered}$$