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Question: Give appropriate reasons for the following statements: The electrical conductivity of acetic acid le...

Give appropriate reasons for the following statements: The electrical conductivity of acetic acid less in comparison to the electrical conductivity of dilute sulphuric acid at a given concentration.

Explanation

Solution

Electrical conductivity will depend on the no. of ions. The more the no. of ions of a particular acid the more is its electrical conductivity. Weak Acid partially dissociates into ions in aqueous solution whereas strong acid fully dissociates into ions in aqueous solution. Acetic acid is a Weak Acid and sulphuric acid is a Strong Acid.

Complete answer:
A weak acid is one that does not dissociate completely in solution; this means that a weak acid does not donate all of its hydrogen ions (H+)({{H}^{+}}) in a solution. So, here acetic acid being weak acid dissociates partially thereby its electrical conductivity is less than sulphuric acid. Dilute sulphuric acid being strong acid dissociates completely. Dissociation of both acetic acid and sulphuric acid is shown as-
CH3COOH+H2O⇌CH3COO−+H3O+C{{H}_{3}}COOH+{{H}_{2}}O\rightleftharpoons C{{H}_{3}}CO{{O}^{-}}+{{H}_{3}}{{O}^{+}}
H2SO4(aq)→2H+(aq)+SO4(aq)2−{{H}_{2}}S{{O}_{4(aq)}}\to 2{{H}^{+}}_{(aq)}+SO_{4(aq)}^{2-}
This is the reason why acetic acid has less electrical conductivity in comparison to the electrical conductivity of dilute sulphuric acid at a given concentration.
Additional Information: Dissociation constant of an acid: The ionization constant is a measure of acid strength. It is represented byKa{{K}_{a}}. The higher the Ka{{K}_{a}} value, the greater the no. of hydrogen ions liberated per mole of acid in the solution and hence stronger is the acid. Low values of Ka{{K}_{a}} mean that the acid does not dissociate well and that it is a weak acid.
The more easily the acid dissociates, and the stronger it is i.e. the weaker the base it is, and less strongly its bonds are held together by electron donation.

Note:
One has to check for the dissociation of the acids to know their electrical conductivity. Whether the acid is weak or strong, it can be known from its dissociation constant. Acetic Acid has less dissociation constant as compared to sulphuric acid. Often times, the Ka{{K}_{a}} value is expressed by using thepKap{{K}_{a}}, the larger the value ofpKap{{K}_{a}}, the smaller the extent of dissociation. A weak acid has a pKap{{K}_{a}} value in the approximate range of −2-2 to +12+12 in water. Acids with pKap{{K}_{a}} value of less than about −2-2 are said to be strong acids.