Question

Use VSEPR theory to predict the molecular geometry around either carbon atom in acetylene, C2H2

a) linear
b) bent
c) trigonal planar
d) tetrahedral
e) octahedral

Answer 1

The carbon atom on the left in acetylene is tetrahedral, while the other two carbon atoms are linear.

Step-by-step explanation:

Because the carbon atom on the left is bonded to four other atoms, we know that it is approximately tetrahedral. The next two carbon atoms share a triple bond, and each has an additional single bond. Because a multiple bond is counted as a single bond in the VSEPR model, each carbon atom behaves as if it had two electron groups. This means that both of these carbons are linear, with C-C=C and C=C-H angles of 180°.