What is the molarity of NaOH, if 15g of NaOH is mixed with 600mL?

M (NaOH) = 15 g

v=600 ml=0.6 l

n (NaOH) = m (NaOH) / M (NaOH)

C=n (NaOH) / v=m (NaOH) / [M (NaOH) v]

C=15g/[40g/mol*0.6 l]=0.625 mol/l

0.625M

[H⁺]=7.5*10⁻²

pOH=14-pH=14+lg[H⁺]

pOH=14+lg (7.5*10⁻²) = 14-1.125=12.875