Question

Which of the following is a weak acid
(A) $C{H_3}COOH$
(B) $HCl$
(C) ${H_2}S{O_4}$
(D) $HN{O_3}$

Answer 1

There are many theories developed till now to explain the acid-base concept of different acids and bases present. Different theories are Bronsted-Lowry theory of acid and base and the lewis acid- base theory.

Complete answer:
So we will discuss the Bronsted-Lowry theory to understand the acid and base phenomenon for the better perspective of the question.
So according to Bronsted-Lowry theory, a Bronsted-Lowry acid is the chemical species which donates the hydrogen ion and the Bronsted-Lowry base is the chemical species that accepts the hydrogen ion.
So, now we have a basic idea regarding the acid and base species.
Moving forward the strong and weak acids are characterised on the basis of their dissociation in the water. I.e. their ability to give hydrogen ions or undergo dissociation.
And as among the given options in the question we can see that the acetic acid does not dissociate properly in the water, it undergoes only partial dissociation.
Let’s look at the dissociation reaction of the acetic acid:

And all the other given acids i.e. hydrochloric acid, sulphuric acid and nitric acid dissociate completely in water and are the strong acids.
So the correct answer to the question is option A. i.e. acetic acid, $C{H_3}COOH$ .

Note:
So, acetic acid being a mild acid is frequently used in daily life in the form of vinegar, which is an important compound in the food industries. It is actually a colourless liquid with a very strong pungent smell which is its characteristic.