Question

Which of the following statements about $pH$ and $ H^+ $ ion concentration is incorrect?

• A. Addition of one drop of concentrated $HCl$ in $ NH_4OH $ solution decreases pH of the solution
• B. A solution of the mixture of one equivalent of each of $ CH_3COOH $ and NaOH has a pH of $7$
• C. pH of pure neutral water is not zero
• D. A cold and concentrated $ H_2SO_4 $ has lower $ H^+ $ ion concentration than a dilute solution of $ H_2SO_4 $

Answer 1

Answer: (B), (D)

$CH _{3} COOH$ is weak acid while $NaOH$ is strong base, so one equivalent of $NaOH$ cannot be neutralised with one equivalent of $CH _{3} COOH$. Hence, one equivalent of each does not have $pH$ value $7$. As the $NaOH$ is a strong base, the solution will be basic having a pH more than $7$ .
So, $ H _{2} \times$ dibasic acid