Question

State whether the pH at the equivalence point in each of the following titrations is expected to be less than 7, equal to 7, or greater than 7. a. Strong acid (e.g. HCl) with strong base (e.g. NaOH) b. Weak acid (e.g. acetic acid, CH3COOH) with strong base (e.g. NaO

Answer 1

Answer:

A. equal to 7

B. greater than 7

Explanation:

a. Strong acid (e.g. HCl) with strong base (e.g. NaOH)

HCl + NaOH ⇒ NaCl + H₂O

The reaction of HCl and NaOH will form a neutral salt, NaCl. So, the pH at the equivalence point will be equal to 7.

b. Weak acid (e.g. acetic acid, CH₃COOH) with strong base (e.g. NaOH)

CH₃COOH + NaOH ⇒ CH₃COONa + H₂O

The reaction of CH₃COOH and NaOH will form a basic salt, CH₃COONa. So, the pH at the equivalence point will be greater than 7.