Chemistry - Complete Pblock- Question with Solution | TestHub

In CH₃−N(SiH₃)₂, the lone pair on N can interact with the vacant d-orbitals of Si ($p\pi -d\pi$ back-bonding), reducing its availability for donation.

Replacing −SiH₃ by −CH₃ removes this N→Si interaction, so the lone pair becomes more available. Therefore, replacing one −SiH₃ by −CH₃ increases lone-pair donating power → (B)

Replacing both −SiH₃ groups by −CH₃ increases it further → (C)

Replacing both −SiH₃ groups by H also removes the N→Si interaction → (D)

Correct: B, C, D