Question

Calculate the pH of the resulting solution if 34.0 mL of 0.340 M HCl(aq) is added to (a) 44.0 mL of 0.340 M NaOH(aq).(b) 24.0 mL of 0.340 M NaOH(aq).

Answer 1

Convert everything to moles. You are given concentration and volume, so you can find moles by the equation: \(concentration \times volume = moles\). Also, note that HCl and NaOH neutralize each other by the reaction: \(HCl + NaOH \rightarrow NaCl + H_2O\). So subtract the two mole amounts from each other. The larger value will be the excess of that amount. Then, find the concentration, which is moles over TOTAL volume.
Finally, you can find the pH, which is: pH= -log[H+]