Question

Which of the following acts as a buffer solution ?

• A. 500 ml of 0.1 M-CH₃COOH + 1 litre 0.1 M-KOH solution mixture
• B. 1 litre of 0.1 M-CH₃COOH + 1 litre 0.1 M-KOH solution mixture
• C. 1 litre of 1 M-CH₃COOH + 500 ml of 1 M-KOH solution mixture
• D. 1 litre 0.1 M-CH₃COOH + 500 ml of 0.2 M-KOH solution mixture

Answer 1

The correct option is C

1 litre of 1 M-CH₃COOH + 500 ml of 1 M-KOH solution mixture

Number of equivalents of $C{H}_{3}COOH=N\times V_{lit}=1\times 1$= 1 eq
Number of equivalents of $KOH=N\times V_{lit}=1\times 0.5$ = 0.5 eq

$C{H}_{3}COOH+KOH\to C{H}_{3}COOK+H_{2}O$
Initially, [$C{H}_{3}COOH$] = 1, [$KOH$] = 0.5, [$C{H}_{3}COOK$] = 0
Finally, [$C{H}_{3}COOH$] = 1 – 0.5 = 0.5, [$KOH$] = 0.5 – 0.5= 0, [$C{H}_{3}COOK$] = 0.5
Since the final solution contains a weak acid($C{H}_{3}COOH$) & its salt of strong base($C{H}_{3}COOK$) , it is a buffer