JEE Advanced 2026 — Paper 1 — CHEM-IV solution

JEE Advanced2026Paper 1CHEM-IV

Consider the following species :

SOCl $_{2}$ , XeOF $_{4}$ , ClF $_{3}$ , ClF $_{5}$ , XeF $_{5}^{+}$ , SO $_{3}^{2 -}$ , XeF $_{3}^{+}$ , SF $_{4}$

List-I contains different molecular shapes and List-II contains total number of species with the same molecular shapes from the given species. Match each entry in List-I with the appropriate entry in List-II and choose the correct option.

List-I	List-II
(P) See-saw	(1) One
(Q) T-Shaped	(2) two
(R) Trigonal Planar	(3) three
(S) Square Pyramidal	(4) four
	(5) zero

A
P $\to$ 1; Q $\to$ 2; R $\to$ 5; S $\to$ 3
B
P $\to$ 5; Q $\to$ 4; R $\to$ 2; S $\to$ 3
C
P $\to$ 3; Q $\to$ 2; R $\to$ 1; S $\to$ 4
D
P $\to$ 1; Q $\to$ 3; R $\to$ 5; S $\to$ 4

Solution

Assign each species using VSEPR.

SOCl $_{2}$ : S has 1 lone pair + 3 bonding (S=O, 2 × S–Cl) $\to$ pyramidal.
XeOF $_{4}$ : Xe has 1 lone pair + 5 bonds $\to$ square pyramidal.
ClF $_{3}$ : Cl has 2 lone pairs + 3 bonds $\to$ T-shape.
ClF $_{5}$ : Cl has 1 lone pair + 5 bonds $\to$ square pyramidal.
XeF $_{5}^{+}$ : Xe $^{+}$ has 1 lone pair + 5 bonds $\to$ square pyramidal.
SO $_{3}^{2 -}$ : S has 1 lone pair + 3 bonds $\to$ pyramidal.
XeF $_{3}^{+}$ : Xe $^{+}$ has 2 lone pairs + 3 bonds $\to$ T-shape.
SF $_{4}$ : S has 1 lone pair + 4 bonds $\to$ see-saw.

Count by shape.

(P) See-saw: SF $_{4}$ only $\to$ one. P $\to$ 1.
(Q) T-shaped: ClF $_{3}$ , XeF $_{3}^{+}$ $\to$ two. Q $\to$ 2.
(R) Trigonal planar: none of these species is trigonal planar $\to$ zero. R $\to$ 5.
(S) Square pyramidal: XeOF $_{4}$ , ClF $_{5}$ , XeF $_{5}^{+}$ $\to$ three. S $\to$ 3.

Mapping P $\to$ 1, Q $\to$ 2, R $\to$ 5, S $\to$ 3 corresponds to option (A).

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