Question

The $pH$ of a $10^{- 9}M$ solution of $HCl$ in water is .

• A. 8
• B. – 8
• C. Between 7 and 8
• D. Between 6 and 7

Answer 1

Answer: (D)

Between 6 and 7

Answer 2

As the solution is acidic, $pH < 7$. This is because $\lbrack H^{+}\rbrack$ from $H_{2}O\lbrack 10^{- 7}M\rbrack$ cannot be neglected in comparison to $10^{- 10}$ M