JEE Main · 2005 · 08 May 2005 · Offline · p-Block Elements

The number of hydrogen atom(s) attached to phosphorus atom in hypophosphorous acid is

(A)zero
(B)two✓ Correct
(C)one
(D)three

Answer: (B)

Solution

Hypophosphorous acid is

H X_{3} PO X_{2}

, and its structure decides the count. Drawn out, the phosphorus carries one

P = O

, one

P - OH

and two direct

P - H

bonds. Only the hydrogen of the

- OH

is ionisable, but the question asks for hydrogens bonded straight to phosphorus, and there are two of those.

JEE Main · 2005 · 08 May 2005 · Offline · Single correct option

Practise more: all JEE Main PYQs on p-Block Elements →

More JEE Main questions on p-Block Elements

Given below are two statements:

Statement I: The number of pairs among [ $SiO_{2}, CO_{2}$ ], $[SnO, SnO_{2}], [PbO, PbO_{2}]$ and $[GeO, GeO_{2}]$ , which contain oxides t …
JEE Main 2026View solution →
A 'p'-block element (E) and hydrogen form a binary cation $(EH_{x})^{+}$ , while $EH_{3}$ on treatment with $K_{2} HgI_{4}$ in alkaline medium gives a precipitate of basic mercury(II)amido-iodine. Given below are first …
JEE Main 2026View solution →
Given below are two statements :

Statement I: The halogen that makes longest bond with hydrogen in HX, has the smallest covalent radius in its group.

Statement II : A group 15 element's hydride $EH_{3}$ has the lowest boiling point among corresponding hydrides of oth …
JEE Main 2026View solution →
Two p-block elements X and Y form fluroides of the type $EF_{3}$ . The fluoride compound $XF_{3}$ is a Lewis acid and $YF_{3}$ is a Lewis base. The hybridization of the central atoms of $XF_{3}$ and $YF_{3}$ respectively are
JEE Main 2026View solution →
Given below are two statements:

Statement I: The correct order in terms of bond dissociation enthalpy is $Cl_{2} > Br_{2} > F_{2} > I_{2}$
Statement II: The correct trend in the covalent character of the metal halides is …
JEE Main 2026View solution →
Given below are two statements :

Statement-I : Element ' X ' and $^{'} Y$ ' are the most and least electronegative elements, respectively among $N, As, Sb$ and P . The nature of the oxides $X_{2} O_{3}$ and …
JEE Main 2026View solution →