Problem: The pH of a 0.021 M solution of a weak acid is 3.95. What is the value of Ka for this acid.a. 5.3x10-3b. 5.9x107c. 6.0x10-7d. 1.7x107e. 6.0x10-8

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FREE Expert Solution

We are being asked to calculate the Ka of a weak acid if 0.021 M solution of the weak acid has a pH of 3.95

We're going to represent the weak acid as HASince we’re dealing with a weak acid and Ka is an equilibrium expression, we will have to create an ICE chart to determine the equilibrium concentration of each species:

HAweak acidproton donor
H2O → will act as the weak baseproton acceptor


Equilibrium reaction:        HA(aq) + H2O(l)  A-(aq) + H3O+(aq)

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Problem Details

The pH of a 0.021 M solution of a weak acid is 3.95. What is the value of Kfor this acid.

a. 5.3x10-3
b. 5.9x107
c. 6.0x10-7
d. 1.7x107
e. 6.0x10-8

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What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Weak Acids concept. If you need more Weak Acids practice, you can also practice Weak Acids practice problems.

What professor is this problem relevant for?

Based on our data, we think this problem is relevant for Professor Halasyamani's class at UH.