What is the approximate CCC bond angle in the compound below?

Question

Quizplus · Accepted Answer

In the given compound, the central carbon atom is bonded to two other carbon atoms. These two carbon atoms are in a linear arrangement and are symmetrically placed on both sides of the central carbon atom. The linear arrangement of these carbon atoms results in an angle of 180° between them. However, since we are interested in the bond angle of the central carbon atom, we only consider one of the two C-C bonds. The bond angle between the central carbon atom and one of the adjacent carbon atoms is therefore half of 180°, which is 90°. However, since the adjacent carbon atoms are not in the same plane as the central carbon atom (they are pointing upwards and downwards), the actual bond angle is slightly less than 90°, which makes D (120°) the most appropriate answer.

What Is the Approximate CCC Bond Angle in the Compound