2 g acetic acid and 3 g sodium acetate are | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(C) The solution is a buffer solution containing a weak acid $(CH_3COOH)$ and its salt with a strong base $(CH_3COONa)$.$pH$ is calculated using the H

Vedclass · Accepted Answer

$4.78$

Vedclass · Answer

(C) The solution is a buffer solution containing a weak acid $(CH_3COOH)$ and its salt with a strong base $(CH_3COONa)$.$pH$ is calculated using the Henderson-Hasselbalch equation: $pH = pK_a + \log(\frac{[Salt]}{[Acid]})$.$1$. Calculate moles of acetic acid $(CH_3COOH)$: Molar mass = $60 \ g/mol$. Moles = $2 \ g / 60 \ g/mol = 0.0333 \ mol$.$2$. Calculate moles of sodium acetate $(CH_3COONa)$: Molar mass = $82 \ g/mol$. Moles = $3 \ g / 82 \ g/mol = 0.0366 \ mol$.$3$. Since the volume is the same $(100 \ mL)$,the ratio of concentrations is equal to the ratio of moles: $\frac{[Salt]}{[Acid]} = \frac{0.0366}{0.0333} \approx 1.1$.$4$. Calculate $pK_a$: $pK_a = -\log(1.8 	imes 10^{-5}) = 5 - \log(1.8) = 5 - 0.255 = 4.745$.$5$. Calculate $pH$: $pH = 4.745 + \log(1.1) = 4.745 + 0.041 = 4.786$.Thus,the $pH$ is approximately $4.78$.

$2 \ g$ acetic acid and $3 \ g$ sodium acetate are present in $100 \ mL$ aqueous solution. What will be the $pH$ of the solution if the ionisation constant of acetic acid is $1.8 \times 10^{-5}$?

Similar Questions

An aqueous buffer is prepared by adding $100 \, mL$ of $0.1 \, mol \, L^{-1}$ acetic acid to $50 \, mL$ of $0.2 \, mol \, L^{-1}$ of sodium acetate. If $pK_a$ of acetic acid is $4.76$,the $pH$ of the buffer is

$A$ buffer solution contains $0.1 \ M$ of acetic acid and $0.1 \ M$ of sodium acetate. What will be its $pH$,if $pK_a$ of acetic acid is $4.75$?

The $pH$ of blood does not appreciably change by a small addition of acid or a base because blood

$A$ buffer solution is formed by a weak acid and its salt with a strong base,or a weak base and its salt with a strong acid. In which of the following pairs is this characteristic found?

$A$ buffer solution with $pH = 9$ is prepared by mixing $NH_4Cl$ and $NH_4OH$. Calculate the number of moles of $NH_4Cl$ dissolved in $1.0 \, L$ of $1.0 \, M \, NH_4OH$ solution. (Given: $K_b(NH_4OH) = 1.8 \times 10^{-5}$)

Vedclass Test Series

Exam Paper Generator

Online Exam Module