Verified Solution • 2025–26 Session moderate

QJEEM21Chf9fa: JEE Main 2021 Chemistry - Class 11 JEEM21Chf9fa Solution: In order to prepare a buffer solution of pH 5.74, sodium…

In order to prepare a buffer solution of pH 5.74, sodium acetate is added to acetic acid. If the concentration of acetic acid in the buffer is 1.0 M, the concentration of sodium acetate in the buffer is ___________ M. (Round off to the Nearest Integer). [Given : pKa (acetic acid) = 4.74]

Step-by-Step Verified Solution

CH3COOH+CH3COONaC{H_3}COOH + C{H_3}COONa [Acidic Buffer]

pH=pka+log⁡[CH3COONa][CH3COOH]{pH} = {p{ka}} + \log {{[C{H_3}COONa]} \over {[C{H_3}COOH]}}

⇒5.74=4.74+log⁡[CH3COONa][CH3COOH]\Rightarrow 5.74 = 4.74 + \log {{[C{H_3}COONa]} \over {[C{H_3}COOH]}}

⇒1=log⁡[CH3COONa][CH3COOH]\Rightarrow 1 = \log {{[C{H_3}COONa]} \over {[C{H_3}COOH]}}

⇒[CH3COONa][CH3COOH]=10\Rightarrow {{[C{H_3}COONa]} \over {[C{H_3}COOH]}} = 10

⇒[CH3COONa]=10×1=10\Rightarrow [C{H_3}COONa] = 10 \times 1 = 10

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