Question

A three-carbon alkene contains two double bonds. Predict its molecular formula? A) C3H4 B) C3H5 C) C3H6

Answer 1

Answer:

A) C3H4

Explanation:

We have to remember that for each carbon we must have 4 bonds. In a three-carbon alkene we will have 2 bonds for the left carbon, 4 bonds for the central carbon and 2 bonds for the right carbon (Figure 1). Therefore we have to add 2 hydrogens in the left carbon and 2 hydrogens for the right carbon. Finally, if we count the number of carbons and hydrogens we will get C3H4.

Answer 2

A three-carbon alkene contains two double bonds. My prediction of its molecular formula is A. C3H4.