In a 0.1000M solution of methanoic acid, [H+]=4.2 x 10^-3M. Calculate the Ka of this acid.

Question

Nora Shelton

Chemistry

5 June, 00:49

In a 0.1000M solution of methanoic acid, [H+]=4.2 x 10^-3M. Calculate the Ka of this acid.

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Answers (1)

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Ean Underwood · Answer 1

In order to determine the Ka of the compound, we can use the expression for the calculation of pH for weak acids which is expressed as:

pH = - 0.5 log Ka

-log (H+) = - 0.5 log Ka

-log (4.2x10^-3) = - 0.5 log Ka

Ka = 1.764x10^-5

Hope this answers the question.