Final answer:
The b) addition of HCl will increase the percentage of ammonia that is converted to the ammonium ion in water, as it reacts with OH− ions and shifts the equilibrium to produce more NH₄+.
Step-by-step explanation:
The reaction of ammonia (NH₃) with water to form ammonium ion (NH₄+) and hydroxide ion (OH−) can be influenced by adding various substances to the solution. The question asks whether the addition of NaOH, HCl, or NH₄Cl would increase the percentage of ammonia converted to the ammonium ion.
- Addition of NaOH: This will not increase the conversion of NH₃ to NH₄+ because NaOH is a strong base that will increase the concentration of OH− ions, which will shift the equilibrium to the left, favoring NH₃ and reducing the percentage of it converting to NH₄+.
- Addition of HCl: This will increase the percentage conversion of NH₃ to NH₄+ because HCl is a strong acid that will react with OH− to form water, thereby shifting the equilibrium to the right to produce more NH₄+.
- Addition of NH₄Cl: This will not increase the conversion of NH₃ to NH₄+ since adding NH₄Cl, which dissociates into NH₄+ and Cl−, increases the concentration of NH₄+ and shifts the equilibrium to the left, again favoring NH₃.