Question

For $H_3PO_3\, and\, H_3PO_4,$ the correct choice is

• A. $H_3PO_3$ is dibasic and reducing
• B. $H_3PO_3$is dibasic and non-reducing
• C. $H_3PO_4$is tribasic and reducing
• D. $H_3PO_3$is tribasic and non-reducing

Answer 1

Answer: (A)

$H_3PO_3$ is dibasic and reducing

Answer 2

$H _{3} P O _{3}$ is a dibasic acid as it has 2 number of replaceable OH groups(Dibasic) attached to phosphorous. The oxyacids of phosphorous are reducing agents. $H _{3} PO _{3}$ is a good reducing agent than $H _{3} PO _{4}$. The reducing nature of these acids is based on the no of hydrogen atoms bonded to the central metal atom. As more number of $H$ attached to phosphorous more is its reducing nature. In the case of $H _{3} P O _{3}$, there is one $P - H$ bond which is responsible for it's reducing character whereas there is no such bonding in case of $H _{3} P O _{4}$.