What are the concentrations of HSO4-, SO42-, and H+ in a 0.28 M KHSO4 solution?
ID: 629078 • Letter: W
Question
What are the concentrations of HSO4-, SO42-, and H+ in a 0.28 M KHSO4 solution? (Hint: H2SO4 is a strong acid; Ka for HSO4- = 1.3 multiplied by 10-2.)Explanation / Answer
HSO4- ===> H+ + SO4= Ka = [H+][SO4=]/[HSO4-] = 1.3 x 10^-2 Let [H+] = x. Then [SO4=] = x and [HSO4-] = 0.28 - x. (x)(x)/(0.28-x) = 1.3 x 10^-2 x^2 = (3.6x10^-3) - (1.3x10^-2)x and you have to go on with the quadratic equation from there. Ordinarily, we would assume that x is so small that [HSO4-] = x. But x turns out to be 0.06 M, so [HSO4-] = 0.28 - 0.06 = 0.22, which is an appreciable difference.