JEE Advanced levelSingle correct optionDifficulty 3 of 3ph200
Match the species in List I with the number of bond pairs and lone pairs on the central atom in List II. List I: (P) ClFX3 (Q) XeFX4 (R) XeFX6 (S) IClX2X−. List II: (1) 2 bond pairs, 3 lone pairs (2) 3 bond pairs, 2 lone pairs (3) 4 bond pairs, 2 lone pairs (4) 6 bond pairs, 1 lone pair.
AP-3, Q-2, R-4, S-1
BP-2, Q-3, R-1, S-4
CP-3, Q-2, R-1, S-4
DP-2, Q-3, R-4, S-1
Answer: D
Central-atom valence electrons (with charge) minus those used gives the lone pairs. ClFX3: 7−3=4 electrons, 2 lone pairs. XeFX4: 8−4=4, 2 lone pairs. XeFX6: 8−6=2, 1 lone pair. IClX2X−: 7+1−2=6, 3 lone pairs. So P-2, Q-3, R-4, S-1.