Question

Valeric acid, HC5H9O2 (Ka = 1.5 ✕ 10−5), is used in the manufacture of magnesium valerate, a nerve-calming agent. What is the hydronium ion concentration (in M) in a 0.737 M solution of HC5H9O2? (Assume Kw = 1.01 ✕ 10−14.)

Answer 1

`[H^+]=0.00332M`

Step-by-step explanation:

Hello,

In this case, considering the dissociation of valeric acid as:

`HC_5H_9O_2 \rightleftharpoons C_5H_9O_2 ^-+H^+`

Its corresponding law of mass action is:

`Ka=([H^+][C_5H_9O_2^-])/([HC_5H_9O_2])`

Now, by means of the change
`x` due to dissociation, it becomes:

`Ka=((x)(x))/(0.737-x)=1.5x10^(-5)`

Solving for
`x` we obtain:

`x=0.00332M`

Thus, since the concentration of hydronium equals
`x`, the answer is:

`[H^+]=x=0.00332M`

Best regards.