JEE Main 2026 · 6 Apr · Shift 1 · Chemistry Q54

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ChemistrySingle correct+4 / -1Question 54 of 75

The pairs among $A=\left[\ce{SO3^2-},\ \ce{CO3^2-}\right]$ , $B=\left[\ce{O2^2-},\ \ce{F2}\right]$ , $C=\left[\ce{CN-},\ \ce{CO}\right]$ , $D=\left[\ce{NH3},\ \ce{H3O+}\right]$ and $E=\left[\ce{MnO4^2-},\ \ce{CrO4^2-}\right]$ that do not have similar Lewis dot structure are

A, B and E

A and E

B, C and D

C and D

Answer and worked solution

Official answer: B

Each pair.

A: $\ce{SO3^2-}$ has a lone pair on S and is pyramidal; $\ce{CO3^2-}$ has none and is trigonal planar. Not similar.
B: $\ce{O2^2-}$ and $\ce{F2}$ are isoelectronic, each a single bond with 3 lone pairs on each atom. Similar.
C: $\ce{CN-}$ and CO are isoelectronic, each a triple bond with a lone pair on each atom. Similar.
D: $\ce{NH3}$ and $\ce{H3O+}$ each have 3 bond pairs and 1 lone pair. Similar.
E: $\ce{MnO4^2-}$ has an unpaired d electron on Mn ( $d^1$ ); $\ce{CrO4^2-}$ has none ( $d^0$ ). Not similar.

Answer: A and E.

(B)

Topics:Covalent bonding and Lewis structures

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JEE Main 2026 · 6 Apr · Shift 1, Chemistry question 54