Question

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

• A. 1.91
• B. 12.7
• C. 2.31
• D. 3

Answer 1

The correct option is B 12.7

$NaOH⟶23+16+1=40$

$NaOH+H_{2}O$

$2g$

no. of mole of $NaOH$=$\frac{2}{40}$

$=0.05$ mol

Molarity=$\frac{2}{40}=0.05M$

$pOH=-\log \left[OH\right]=-\log \left(0.05\right)$

$pOH=1.3$

$pH=14-1.3=12.7$