Question

The pH at the equivalence point in any titration is the pH of the salt solution formed. At the equivalence point of the titration, the solution contains sodium benzoate and water. The passage states that benzoic acid is a weak acid; therefore, its conjugate base, the benzoate anion, is a stronger base than OH- and reacts with water to produce OH- and undissociated benzoic acid. The resulting solution then has a pH > 7, because of the hydroxide ions produced by this reaction. The reaction of an ion such as benzoate ion with water is called hydrolysis.

A. < 4

B. > 4 and < 7

C. = 7

D. > 7

Answer 1

D. > 7

Step-by-step explanation:

Benzoic acid, HX, is a weak acid that reacts with OH- as follows:

HX + OH- → X- + H2O

Where X- is produced, the conjugate base of benzoic acid.

As benzoic acid is a weak acid, benzoate ion is a strong base. A strong base has pH > 7. Right option is:

D. > 7