Question

0.3665 g of HCl gas was passed through $100c{m}^3$ of 0.2 M NaOH solution. The pH of the resulting solution would be

• A. 1
• B. 13
• C. 5
• D. 8

Answer 1

The correct option is B 13

0.365 g of HCl $=\frac{0.365}{36.5}=0.01mole$
$100c{m}^3$ of 0.2 M NaOH $=\frac{0.2}{1000}\times 100=0.02mole$
NaOH left unneutralized = 0.01 mole
Volume of solution = 100 ml
$\therefore$ Molarity of NaOH in the solution $=\frac{0.01}{100}\times 1000=0.1M={10}^{-1}M$
$\therefore \left[H^{+}\right]=\frac{{10}^{-14}}{{10}^{-1}}={10}^{-13}M$
$\therefore pH=13$