What is the pH of the resulting solution when equal volumes of 0.1 M NaOH and 0.01 M HCl are mixed?

One mole of NaOH is completely neutralised by one mole of HCl.Hence, 0.01 mole of NaOH will be completely neutralised by 0.01 mole of HCl.NaOH left unneutralised = 0.1 - 0.01 mol                                                   = 0.09 molAs equal volumes of two solutions are mixed,[OH]-=0.092=0.045M⇒ pOH=-log(0.045)=1.35∴ pH=14-1.35=12.65