Step 1: Identify that NH4Cl is an acidic salt formed from the weak base NH3 (ammonia) and the strong acid HCl (hydrochloric acid).
Step 2: Recognize that when NH4Cl dissolves in water, it dissociates into NH4+ (ammonium ion) and Cl- (chloride ion).
Step 3: Understand that the NH4+ ion can donate a proton (H+) to water, forming NH3 and H3O+ (hydronium ion), which makes the solution acidic.
Step 4: Use the formula for the dissociation of NH4+: NH4+ + H2O ⇌ NH3 + H3O+. This shows that NH4+ increases the concentration of H3O+ in the solution.
Step 5: Calculate the concentration of H3O+ produced from the 0.1 M NH4Cl solution. The dissociation constant (Ka) for NH4+ is approximately 5.6 x 10^-10.
Step 6: Set up the equilibrium expression and solve for the concentration of H3O+ to find the pH: pH = -log[H3O+].
Step 7: After calculations, find that the pH of the 0.1 M NH4Cl solution is approximately 5.1.
