Question

How many grams of hydroiodic acid are dissolved in 500. mL of a solution with a pH of 1.2?

Answer 1

Consider,

`HI(aq) rightleftharpoons H^(+)(aq) + I^(-)(aq)`

If `"pH" = 1.2`, then,

`[H^+] = 10^-1.2 = 0.0631"M"` at equilibrium.

`HI` is a strong acid, so generally `[H^+] = [HI] = 0.0631"M"`.

Hence,

`0.500"L" * 0.0631"M" * (127.9"g")/"mol" approx 4.03"g"`

of `HI` are dissolved in this very acidic solution.