What is the pH of a solution made by mixing 100.00mL of 0.020M calcium hydroxide with 50.00 mL of 0.100M NaOH?

Now of moles of hydroxide ion in .02/10 moles Ca(OH)2=.002moles*2(as 1 mole of it contains 2 moles Hydroxides.)=.004moles.Now .1mole NaOH has .1mole OH-.therefore no.of moles of hydroxides in 50ml of the solution=.1/20 =.005moles. therefore 150ml solution has .009 moles. therefore 1 liter has=.009/150 *1000=9/150=.06moles. therefore pOH=-log.06=2log6=1.6.therefore pH=14-1.6=12.78.