Question

Consider the three solutions of 1 M concentration
a. Sodium acetate $\left(C{H}_{3}COONa\right)$
b. Acetic acid + Sodium acetate($C{H}_{3}COOH+(C{H}_{3}COONa$)
c. Acetic acid ($C{H}_{3}COOH$)
The pH of these solutions will lie in the following sequence:

• A. $c<b<a$
• B. $b<a<c$
• C. $a<b<c$
• D. $c<a<b$

Answer 1

The correct option is A $c<b<a$

Acetic acid is a weak acid. Its pH will be less than 7. Sodium acetate is a salt of strong base and weak acid. Its pH will be greater than 7. The pH of mixture of acetic acid and sodium acetate (buffer) will be in between the pH of acetic acid and sodium acetate.
Hence, the order of the pH is $C{H}_{3}COOH<C{H}_{3}COOH+C{H}_{3}COONa<C{H}_{3}COONa$.
Hence, the correct option is $c<b<a$.