Question

Which compound releases hydroxide ions in an aqueous solution?

Answer 1

Answer:

The correct answer is option 4.

Explanation:

Substance which releases hydroxide ions($OH^-$) in an aqueous solution are termed as bases.

Substance which releases proton ($H^+$) in an aqueous solution are termed as acids.

From the given options:

$CH_3COOH$ : It is an weak organic acid known as acetic acid. Being acid it releases $[H&+]$ ion in an aqueous solution.

$CH_3COOH(aq)\rightarrow CH_3COO^-(aq)+H^+(aq)$

$CH_3COH$ : It is an alcohol named methanol and it is slightly acidic.They gives $H^+$ ions and alkoxiode ions.

$CH_3COH(aq)\rightarrow CH_3CO^-(aq)+H^+(aq)$

$HCl$ : It is strong acid known as hydrochloric acid. Being highly acidic it releases $[H&+]$ ion in an aqueous solution.

$CH_3COOH(aq)\rightarrow Cl^-(aq)+H^+(aq)$

$KOH$ : It is strong base known as potassium hydroxide. Being highly acidic it releases $[H&+]$ ion in an aqueous solution.

$KOH(aq)\rightarrow K^+(aq)+OH^-(aq)$

Answer 2

4- KOH

KOH is a strong base. In water it dissociates as 
KOH--> K+ + OH- 
A is acetic acid, a weak acid 
CH3OH is an alcohol, weakly acidic in water 
HCl is a strong acid.