Which of the following acids has the lowest pH?0.1 M HBO, pK_a = 2.430.1 M HA, pK_a = 4.550.1 M HMO, pK_a = 8.230.1 M HST, pK_a = 11.89pure water

Question

Quizplus · Accepted Answer

The lower the pKa/pKs value, the stronger the acid. Among the given options, HBO has the lowest pKa value (2.43). The pH of a 0.1 M solution of HBO can be calculated as follows:
pH = pKa + log([A-]/[HA])
pH = 2.43 + log([O2B-]/[HBO])
At equilibrium, [O2B-] = [H+], and [HBO] = 0.1 M - [H+]. Substituting these values in the equation, we get:
pH = 2.43 + log([H+]/[0.1 M - H+])
At the pH where [H+] = [O2B-], the logarithmic term becomes 0 and pH = pKa. At lower pH values, the [H+] concentration dominates and pH decreases. Therefore, the pH of 0.1 M HBO will be lower than the others, making it the strongest acid among the given options.

Which of the Following Acids Has the Lowest PH?0