Chapter 12, Problem 52A

Interpretation Introduction

Interpretation:

The molecular structure of a given molecule is to be predicted and the bond angle is to be written.

Concept introduction:

VSEPR theory helps to draw the molecular shape as:

Total number of valence electron pairs	Number of bond pairs	Number of lone pairs	Geometry and shape
2	2	0	linear
3	3	0	Trigonal planar
	2	1	bent
4	4	0	Tetrahedral
	3	1	Pyramidal
	2	2	Bent

Answer to Problem 52A

The molecular structure of ${\mathrm{C}}_2{\mathrm{H}}_2$ is linear.

The $\mathrm{H}-\mathrm{C}-\mathrm{C}$ bond angle is $180°$ .

Explanation of Solution

Lewis structure of ${\mathrm{C}}_2{\mathrm{H}}_2$ is:

It shows, there are 2 bond pairs and no lone pairs around the carbon atom. Therefore, by VSEPR theory its shape is linear. Therefore, the $\mathrm{H}-\mathrm{C}-\mathrm{C}$ bond angle is $180°$ .

Conclusion

Thus, acetylene is linear with bond angle $180°$ .