Question

What is bond angle O-S-O in $\text{SO}_2$ molecule?

• A. $107^\circ$
• B. $180^\circ$
• C. $90^\circ$
• D. $119.5^\circ$

Hint:

For $\text{sp}^2$ configurations containing a single lone pair (like $\text{SO}_2$ or $\text{O}_3$), the strong repulsion from that lone pair always pinches the bond angle to a value slightly below the clean trigonal planar threshold of $120^\circ$.

Answer 1

The Correct Option is D

Step 1: Understand the question.
We must find the O-S-O bond angle in the $\text{SO}_2$ molecule. We use VSEPR theory, which predicts shape from electron pairs around the central atom.

Step 2: Count groups around sulfur.
Sulfur is the central atom. It forms bonds with two oxygen atoms and also keeps one lone pair of its own. So it has 2 bonding regions plus 1 lone pair, giving a steric number of 3.

Step 3: Find the hybridisation.
A steric number of 3 means $sp^2$ hybridisation.

Step 4: Find the ideal angle.
A perfect $sp^2$ shape is trigonal planar with angles of $120^\circ$.

Step 5: Adjust for the lone pair.
A lone pair pushes harder than bonding pairs, so it squeezes the two S=O bonds a little closer. This bends the molecule and lowers the angle slightly below $120^\circ$, to about $119.5^\circ$.

Step 6: Pick the answer.
The O-S-O angle is about $119.5^\circ$, which is option 4.
\[ \boxed{119.5^\circ} \]