Question

Assertion :pH of 0.1 M acetic acid is not equal to 1. Reason: Acetic acid is a mono basic acid.

• A. Both assertion and reason are correct and reason is the correct explanation of the assertion.
• B. Both assertion and reason are correct, but reason is not the correct explanation of the assertion.
• C. Assertion is correct, but reason is incorrect
• D. Assertion is incorrect, but reason is correct

Answer 1

The correct option is B Both assertion and reason are correct, but reason is not the correct explanation of the assertion.

For reason:

A monobasic acid is an acid that has only one hydrogen ion to donate to a base in an acid-base reaction. Therefore, a monobasic molecule has only one replaceable hydrogen atom.

For assertion:

The reaction that occurs when acetic acid dissociates in water is

$C{H}_{3}COOH$ + $H_{2}O$ $\rightleftharpoons$ $C{H}_{3}CO{O}^{-}$ + $H_3{O}^{+}$

It is given that 10 mL of 1 M acetic acid is diluted to 100 mL in water. Thus, the initial acetic acid concentration is

$\frac{\left(0.01liter\right)\left(1mol/liter\right)}{\left(0.100tlitertotalvolume\right)}=0.1M$ acetic acid.

Once the acetic acid is diluted in water, the dissociation reaction begins and continues until it reaches equilibrium.

Thus, Assertion is correct because reason is unable to justify assertion.

Option B is correct.