Question

What is the pH for the solution made from 11.10 mL of 0.278 M HCl solution mixed with 70.90 mL of 0.1300 M ammonia solution ? Note that the pKa for NH4+ is 9.241

8.94
9.24
8.77
9.72
9.54

Answer 1

Hi Lucinda:

This is a buffer:

pH = pKa + log [base] / [acid]

pH = 9.241 + log [70.90 x 0.1300] /
[ 11.10 x 0.278]

= 9.72

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Zareh Darakjian, Ph.D.

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