Question

The electronegativity of $C,H,O,N$ and $S$ are $2.5,2.1,3.5,3.0$ and $2.5$ respectively. Which of the following bond is most polar?

• A. $O-H$
• B. $S-H$
• C. $N-H$
• D. $C-H$

Answer 1

Answer: (A), (C)

The correct options are
A $O-H$
C $N-H$

If the electronegativity difference between two atoms is more than the bond between them is more polar.

$O-H\to 3.5-2.1=1.4$

$S-H\to 3.5-2.5=1$

$N-H\to 3.0-2.1=0.9$

$C-H\to 2.5-2.1=0.4$

So, $O-H$ bond is more polar among the given.

Hence option A is correct.