Statement I: Tetrahedral complexes of the type [MA2B2] do not show geometrical isomerism.
Statement II: In a tetrahedral complex, the relative positions of the unidentate ligands attached to the central metal atom are the same with respect to each other.
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Both Statement I and Statement II are correct and Statement II is the correct explanation of Statement I.
Geometrical isomerism needs two different arrangements of the same ligands around the metal, such as cis (adjacent) and trans (opposite).
Statement I: Tetrahedral complexes of the type [MA2B2] do not show geometrical isomerism. — True. Only one form of a tetrahedral [MA2B2] complex exists; cis-trans isomers are found for square planar [MX2L2] and octahedral [MX2L4] complexes, not tetrahedral ones.
Statement II: In a tetrahedral complex, the relative positions of the unidentate ligands attached to the central metal atom are the same with respect to each other. — True. Each corner of a tetrahedron is adjacent to all three other corners, so every pair of positions is related in the same way.
Why Statement II explains Statement I?
Since every pair of corners is equivalent, the two A ligands are always next to each other, whichever corners they take.
No “opposite” (trans) arrangement exists, so only one form is possible, and that is why tetrahedral complexes show no geometrical isomerism.
NCERT (2026-27 edition):
5.4.1 Geometric Isomerism (Example 5.4) – “Tetrahedral complexes do not show geometrical isomerism because the relative positions of the unidentate ligands attached to the central metal atom are the same with respect to each other.”