Equal volumes of 0.1 M HCl and 0.1 M acetic acid (K_a=1.8x10^-5) are compared (separate solutions, 298 K). Select the correct statement(s).

[H+] in HCl is roughly 75 times that in acetic acid.

The pH of the HCl solution is lower than that of acetic acid.

Both solutions need the same amount of NaOH for complete neutralisation.

[H+] in HCl is roughly 75 times that in acetic acid.

The pH of the HCl solution is lower than that of acetic acid.

The pH of the acetic acid solution is about 1.87.

Both solutions need the same amount of NaOH for complete neutralisation.

JEE Main levelOne or more correct optionsDifficulty 2 of 3ie086

Equal volumes of $0.1 M$ $HCl$ and $0.1 M$ acetic acid ( $K_{a} = 1.8 \times 1 0^{- 5}$ ) are compared (separate solutions, 298 K). Select the correct statement(s).

HCl

[H X^{+}] = 0.1

, pH 1. Acetic acid:

[H X^{+}] = 1.8 \times 1 0^{- 5} \times 0.1 = 1.34 \times 1 0^{- 3}

, pH 2.87, so the ratio is

0.1/1.34 \times 1 0^{- 3} \approx 75

. Equal moles of acid are present, so equal

NaOH

is needed. The statement of pH 1.87 is wrong.