Question

Problem Page

An analytical chemist is titrating

199.2mL

of a

0.5800M

solution of formic acid

H2CO2

with a

1.000M

solution of

NaOH

. The

pKa

of formic acid is

3.74

.Calculate the pH of the acid solution after the chemist has added

138.0mL

of the

NaOH

solution to it.

Note for advanced students: you may assume the final volume equals the initial volume of the solution plus the volume of

NaOH

solution added.

Round your answer to

2

decimal places.

=pH

Answer 1

THEREFORE pH = 14 - pOH

= 14 - 4.176

= 9.82

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IN THE GIVEN PROBLEM ALL THE WEAK ACID CONSUMED. EXCESS OF SODIUM HYDROXIDE IS PRESENT . SODIUM FORMATE IS ALSO PRESENT WHICH IS ALSO A BASE. CONCENTRATION OF SODIUM FORMATE NEED NOT BE CONSIDERED IN CALCULATION.