Question

Problem PageQuestion A student prepares a aqueous solution of butanoic acid . Calculate the fraction of butanoic acid that is in the dissociated form in his solution. Express your answer as a percentage. You will probably find some useful data in the ALEKS Data resource.

Answer 1

Incomplete question: A student prepares a 0.54 mM aqueous solution of butanoic acid...

The answer is: The percentage of dissociation is 15.4%

Step-by-step explanation:

Given:

Ka = 1.51x10⁻⁵

Concentration = 0.54 mM = 0.54x10⁻³M

The reaction is:

C₄H₈O₂ = C₄H₇O₂⁻ + H⁺

I 0.54x10⁻³ 0 0

E 0.54x10⁻³(1-x) 0.54x10⁻³x 0.54x10⁻³x

Where x is the degree of dissociation

`Ka=([H^(+)][C_(4)H_(7)O_(2)^(-) )/([C_(4)H_(8)O_(2) ) \\1.51x10^(-5) =(0.54x10^(-3)x^(2) )/(1-x) \\x^(2) +0.028x-0.028=0\\x_(1) =0.154\\x_(2) =-0.182`

We will choose the positive value

x = 0.154

The percentage of dissociation is 15.4%