Question

Which of the following molecule have a centre of symmetry?

• A. $C{O}_2$
• B. $S{O}_2$
• C. $BC{l}_3$
• D. $H_{2}O$

Answer 1

The correct option is A $C{O}_2$

The centre of symmetry is any point in space such that any group on the molecule can be reflected back through that point at an equal distance but in the opposite direction as an equivalent/identical group is found.

$S{O}_2$ and $H_{2}O$ are V shaped so they does not find identical groups at equal distance in opposite direction so they lack centre of symmetry. Also, $BC{l}_3$ is trioangular in shape which doesnot have identical group at oppositee direction. Thus, compound (b), (c) and (d) lacks centre of symmetry.


$C{O}_2$ is a linear molecule which has oxygen group at opposite direction in equal distance. Thus, it has centre of symmetry.