Question

1. Calculate the [H3O+] of a 1.93 M HBrO solution at 25 ºC.

please show work.

Answer 1

To do this, you need to show the reaction involved of the hydrolisis of this compound, and you should take account of the Ka of this acid, because HBrO is a medium strong acid, but it does not dissociate completely in solution. The Ka reported is 2x10^-9. Now the reaction, along with the ICE chart to calculate the H3O+ is:

r: HBrO + H₂O <--------> H₃O⁺ + BrO^-   Ka = 2x10^-9
i: 1.93 0 0
e: 1.93-x x x

Writting the expression for the equilibrium constant:
2x10^-9 = x² / 1.93-x
Ka is a very small value, so we can assume that x would be very small too, and we can neglect the substract of 1.93-x to 1.93 only. Solving for x:
2x10^-9 * 1,93 = x²
x = 6.21x10^-5 M = [H₃O⁺]

Hope this helps