2g of NaOH is dissolved in water to make 1L solution. What is the pH of solution?

Weight of NaOH dissolved = 2g

$\therefore \text{ Equivalent of }\mathrm{NaOH}\text{ dissolved }=\frac{{\displaystyle 2}}{{\displaystyle 40}}$

${\mathrm{N}}_{\mathrm{NaOH}}=\frac{2}{40}=0.05$

$[\mathrm{OH}{]}^{-}=0.05=5\times {10}^{-2}$

$\mathrm{pOH}=-\log \left[{\mathrm{OH}}^{-}\right]$

$=-\log \left(5\times {10}^{-2}\right)=1.3010$

pH+pOH =14

pH =14- pOH = 14- 1.3010= 12.699