An analytical chemist in a food-testing laboratory prepares a 0.0240 mol dm-3 aqueous solution of a newly synthesized monoprotic acid to evaluate its potential as a preservative. At 298 K, the pH of this solution is measured to be 3.12.
What is the value of the acid dissociation constant (KaK_{\text{a}}Ka) for this acid, in mol dm−3\text{mol dm}^{-3}mol dm−3?
3.16×10−23.16 \times 10^{-2}3.16×10−2
2.40×10−52.40 \times 10^{-5}2.40×10−5
7.59×10−47.59 \times 10^{-4}7.59×10−4
5.75×10−75.75 \times 10^{-7}5.75×10−7
