What would be the pH of a solution obtained by mixing 5g of acetic acid and 7.5g of sodium acetate and making the volume equal to 500 mL ? (Ka =1.75 ×10-5, PKa=4.76)

Question

What would be the pH of a solution obtained by mixing 5g of acetic acid and 7.5g of sodium acetate and making the volume equal to 500 mL ? (Ka =1.75 ×10-5, PKa=4.76) (A) pH=4.70 (B) pH< 4.70 (C) pH of solution will be equal to pH of acetic add (D) 4.76 < pH< 5.0

Tardigrade Admin · Accepted Answer

pH=pKa+log ([salt]/[acid]) =4.76+log ((7.5/500)/(5)500)=4.7+log 1.5=4.87 Hence correct answer is 4.76 < pH< 5.0

Q. What would be the $p H$ of a solution obtained by mixing $5 g$ of acetic acid and $7.5 g$ of sodium acetate and making the volume equal to $500 m L$ ?
$(K_{a} = 1.75 \times 1 0^{- 5}, P K_{a} = 4.76)$

$p H = 4.70$

$p H < 4.70$

pH of solution will be equal to pH of acetic add

$4.76 < p H < 5.0$

$p H = p K_{a} + l o g \frac{[ s a lt ]}{[ a c i d ]}$
$= 4.76 + l o g \frac{\frac{7.5}{500}}{\frac{5}{500}} = 4.7 + l o g 1.5 = 4.87$
Hence correct answer is $4.76 < p H < 5.0$

Q. What would be the pH of a solution obtained by mixing 5g of acetic acid and 7.5g of sodium acetate and making the volume equal to 500mL ? (Ka​=1.75×10−5,PKa​=4.76)

pH=4.70

pH<4.70