Question

${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}$ is a:
A. monobasic acid
B. dibasic acid
C. neutral compound
D. weak alkali

Answer 1

Hint: ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}$ is known as peroxide. It has an oxygen-oxygen link and two hydrogens attached with each oxygen. It can donate two protons. Hydrogen peroxide can neutralize two base molecules.

Complete step by step solution:
The molecule that can donate proton is known as acid whereas the compound that can accept proton is known as a base.
The power of acceptance of protons of a base is defined as the basicity and power of donation is defined as the acidity of an acid.
Basicity of an acid is defined as the power of an acid to neutralize a base. The basicity of an acid depends upon the number of protons donated by an acid to neutralize the base.
The acidity of a base is defined as the power of a base to neutralize an acid. The acidity of a base depends upon the number of protons accepted by the base to neutralize the acid.
The structure of hydrogen peroxide is as follows:
$\text{H}-\text{O}-\text{O}-\text{H}$
Hydrogen peroxide has two hydrogen atoms that can be donated to neutralize the bases. So, hydrogen peroxide will neutralize two base molecules.
Monobasic acid means that the acid can donate one proton only to neutralize the one base molecule, so option (A) is incorrect.
Dibasic acid means that the acid can donate two protons to neutralize two base molecules so, option (B) is correct.
Hydrogen peroxide donates protons, so it is an acidic compound, not a neutral compound, so option (C) is incorrect.
Weak alkali partially dissociates to give hydroxide ion whereas the hydrogen peroxide gives hydronium ion so, option (D) is incorrect.
So, hydrogen peroxide ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}$ is dibasic acid.

Therefore, option (B) dibasic acid is correct.

Note: Basicity of an acid defines the number of protons that can be donated, not the total number of protons that an acid has. For example, consider boric acid,${\text{H}}_{\text{3}}\text{B}{\text{O}}_{\text{3}}$, it has three $-\text{OH}$ so, it can donate three protons so,, it should be tribasic. Boric acid donates one proton only so it is monobasic only. Acid accepts electrons. The base loses electrons. Alkali metals lose electrons, so their compounds behave as a base.