A student studies the diffusion of ammonia gas, $\text{NH}_3$, and hydrogen chloride gas, $\text{HCl}$. Two apparatus setups are arranged as shown at room temperature and pressure. The damp red litmus paper in apparatus 1 changes colour after 30 seconds. How long will it take for the damp blue litmus paper in apparatus 2 to change colour?
- A21 seconds
- B30 seconds
- C64 seconds
- DThe damp blue litmus paper does not change colour.