Question

The correct option for the number of bending modes of vibration in each of H$_2$O, CS$_2$, and SO$_2$ molecules, respectively, is

• A. 1, 2 and 2
• B. 2, 2 and 1
• C. 2, 1 and 2
• D. 1, 2 and 1

Hint:

In polyatomic molecules, the number of bending modes corresponds to the number of non-linear vibrations, while linear molecules have only one bending mode.

Answer 1

The Correct Option is D

Step 1: Analyzing H$_2$O.
H$_2$O (water) has two bending modes of vibration. This is because it is a bent molecule with two non-linear vibrational modes.
Step 2: Analyzing CS$_2$.
CS$_2$ (carbon disulfide) has only one bending mode, as it is a linear molecule with a single bending vibration possible.
Step 3: Analyzing SO$_2$.
SO$_2$ (sulfur dioxide) also has two bending modes, as it is a bent molecule with two possible non-linear bending modes.
Step 4: Conclusion.
Thus, the number of bending modes for H$_2$O, CS$_2$, and SO$_2$ are 2, 1, and 2, respectively. The correct answer is (C) 2, 1 and 2.