Ionic Equilibrium Question 1
Question 1 - 24 January - Shift 1
The dissociation constant of acetic is $x \times 10^{-5}$.
When $25 mL$ of $0.2 M CH_3 COONa$ solution is mixed with $25 mL$ of $0.02 M CH_3 COOH$ solution, the $pH$ of the resultant solution is found to be equal to 5 . The value of $x$ is
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Answer: (10)
Solution:
Formula: Buffer solution
Buffer of HOAc and $NaOAc$
$pH=pKa+\log \frac{0.1}{0.01}$
$5=pKa+1$
$pKa=4$
$Ka=10^{-4}$
$x=10$
