Good reducing nature of $\mathrm{H}_{3} \mathrm{PO}_{2}$ is attributed to the presence of

JEE Main · 2019 · 09 Jan 2019 · Shift 2 · p-Block Elements

Good reducing nature of

H_{3} PO_{2}

is attributed to the presence of

(A)Two P - OH bonds
(B)One P - H bond
(C)Two P - H bonds✓ Correct
(D)One P - OH bond

Answer: (C)

Solution

Hypophosphorous acid,

H X_{3} PO X_{2}

, is built as

H X_{2} P (= O) (OH)

: the phosphorus carries one

P - OH

group, one

P = O

bond, and two

P - H

bonds. Only the

P - OH

hydrogen is acidic, but it is the two

P - H

bonds that make the acid such a good reducing agent, because those hydrogens are readily given up as the phosphorus is oxidised toward

P - OH

JEE Main · 2019 · 09 Jan 2019 · Shift 2 · Single correct option

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