Question

40 mg of pure sodium hydroxide is dissolved in 10 litres of distilled water. The pH of the solution is

• A. 9.0
• B. 10
• C. 11
• D. 12

Answer 1

Answer: (B)

$\left[NaOH\right]=\frac{40\times 10^{-3}}{40\times 10}=10^{-4}M$
$\left[O{H}^{-}\right]=10^{-4}M<br/>H^{+}=10^{-10}M$
$pH=10$