The question is asking to utilize the method of the RICE (or sometimes called just ICE)...
4.13 Just as pH is the negative logarithm of [H3O+], pKa is the negative logarithm of Ka, pKa=−logKa The Henderson-Hasselbalch equation is used to calculate the pH of buffer solutions: pH=pKa+log[base][acid] Notice that the pH of a buffer has a value close to the pKa of the acid, differing only by the logarithm of the concentration ratio [base]/[acid]. Part B How many grams of dry NH4Cl need to be added to 2.10 L of a 0.400 M solution of ammonia,...