what is the pH when a 5 mL solution of 30 mL HC2H3O2 is diluted with 25 mL of H2O? The pH of 30 mL HC2H3O2 solution is 2.52 & pKa= 4.74
Stock solution is 30mL acid with pH = 2.52 and pKa = 4.74
The concentration of acid to be calculated from the formula
pH = 1/2 [ pKa -log C]
Now 5 mL of this solution is diluted with water to make it 25 mL.
The [acid] / molarity is calculated as M1V1 = M2V2 .
i) concentration of 30mL solution.
2.52 = 1/2[4.74 -log C]
log C = -0.30
and C= 0.5M
Part 2 )5 mL of this 0.5M solution is diluted to 25 mL
5x0.5 = 25 x M
or mmolarity = 0.1 M
pH of this solution = 1/2 [4.74 - log 0.1]
= 1.87
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