Paper: CSIR-NET December 2017 · Subject: Physical Chemistry · Chapter: Group Theory · Topic: Character Tables · Marks: 2 · Difficulty: Medium
The -orbital $\pi_{\mathrm{u}}$ of ethylene, when placed in the xy -plane with the $\mathrm{C}=\mathrm{C}$ bond aligned to the x -axis, transforms according to the irreducible representation (Use Table-1)
(a)au
(b)$\mathrm{b}_{1 \mathrm{u}}$
(c)$\mathrm{b}_{2 \mathrm{u}}$
(d)$\mathrm{b_{3u}}$
Answer
Answer: B ✓ checked by 4AB · confidence high
Explanation
With the molecule in the xy plane and C=C along x, the π orbital is built from p_z and the bonding πu transforms as z — b₁u (b).