A bottle of ammonia and a bottle of dry hydrogen chloride connected through a long tube are opened s — States of Matter and Gaseous State Chemistry Question

💡 Solution & Explanation

# Solution: Location of Ammonium Chloride Ring Formation ## Given Information - Ammonia ($NH_3$) and hydrogen chloride ($HCl$) gases diffuse from opposite ends of a tube - They react: $NH_3 + HCl \rightarrow NH_4Cl$ (white solid) ## Step-by-Step Analysis **Step 1: Compare Molar Masses** - $M(HCl) = 36.5$ g/mol - $M(NH_3) = 17$ g/mol **Step 2: Apply Graham's Law of Diffusion** $$\text{Rate of diffusion} \propto \frac{1}{\sqrt{M}}$$ Since $HCl$ is heavier, it diffuses **slower** than $NH_3$. $$\frac{\text{Rate}_{NH_3}}{\text{Rate}_{HCl}} = \sqrt{\frac{36.5}{17}} \approx 1.47$$ **Step 3: Determine Meeting Point** $NH_3$ travels faster and covers more distance in the same time. Therefore, $HCl$ (the slower gas) doesn't travel as far before meeting $NH_3$. **Step 4: Locate the Ring** The white $NH_4Cl$ ring forms where the two gases first meet, which is **closer to the $HCl$ bottle** (or farther from the $NH_3$ bottle). ## Answer The ring forms **closer to the hydrogen chloride end** of the tube because $HCl$ diffuses more slowly than ammonia. *(Option B likely states this position correctly)*