Question

Which bond angle of the following molecule has the largest value?

• A. $\angle HCF$
• B. $\angle ClCF$
• C. $\angle HCD$
• D. $\angle ClCD$

Answer 1

The correct option is C $\angle HCD$

For methane derivatives, instead of directing equivalent $s{p}^3$ orbitals toward all four substituents, orbitals get oriented such that more electronegative element occupies the orbital having less $s$ character and vice versa [Bent's rule].
(Electronegativity of given elements: $F>Cl>H>D$)
As a result of this, $\angle HCD$ becomes the largest (more $s$ character) and $\angle ClCF$ becomes the smallest (more $p$ character).