Question

The acid dissociation constant of uric acid is $K_a=4.0\times {10}^{-6}M$. The $pH$ of a sample is $\mathrm{6.0.}$ What is the ratio of urate ion to uric acid in the urine?

• A. $2.0$
• B. $4.0$
• C. $6.0$
• D. $0.25$

Answer 1

The correct option is B $4.0$

$pH=p{K}_a+log\frac{salt}{acid};$

Subsituting,

$6=-log4\times {10}^{-6}+log\frac{salt}{acid}$

$log\frac{salt}{acid}=log4$

$\frac{salt}{acid}=4$.