Question

Alkali which dissociates only partially in aqueous solution: 1. Lithium hydroxide 2. Calcium hydroxide 3. Potassium hydroxide 4. Sodium hydroxide​

Answer 1

Lithium Hydroxide only dissociates partially in aqueous solution.

Answer 2

Alkali which dissociates only partially in aqueous solution is 1. Lithium hydroxide.

Explanation:

• A strong alkali dissociates completely in an aqueous solution whereas a weak alkali dissociates partially in an aqueous solution.
• Calcium hydroxide dissociates completely in an aqueous solution.

        $\[Ca{(OH)_2} \to C{a^{2 + }} + 2O{H^ - }\]$

• Potassium hydroxide also dissociates completely in an aqueous solution.

        $\[KOH \to {K^ + } + O{H^ - }\]$

• Sodium hydroxide dissociates completely in an aqueous solution as:

        $\[NaOH \to N{a^ + } + O{H^ - }\]$

• Lithium hydroxide dissociates in the aqueous solution as:

       $\[LiOH \rightleftharpoons L{i^ + } + O{H^ - }\]$

• This is because the hydroxide ion form bonds with water. Also, the lithium ion, being smaller in size gets extensively solvated. Thus, in lithium hydroxide, due to solvation, dissociation occurs only partially.