Which of the following statements concerning hydrocarbons is/are correct?

1.

Saturated hydrocarbons may be cyclic or acyclic molecules.

2.

An unsaturated hydrocarbon molecule contains at least one double bond.

3.

Ethylenediamine, H2NCH2CH2NH2, is an example of a saturated hydrocarbon.

1. Saturated hydrocarbons may be cyclic or acyclic molecules.

2. An unsaturated hydrocarbon molecule contains at least one double bond.

Explanation:

Hello,

In this case, hydrocarbons are defined as the simplest organic compounds containing both carbon and hydrogen only, for that reason we can immediately discard the third statement as ethylenediamine is classified as an amine (organic chain containing NH groups).

Next, as saturated hydrocarbons only show single carbon-to-carbon bonds and carbon-to-hydrogen bonds, they may be cyclic (ring-like-shaped) or acyclic (not forming rings), so first statement is true

Finally, since we can find saturated hydrocarbons which have single carbon-to-carbon and carbon-to-hydrogen bonds only and unsaturated hydrocarbons which could have double or triple bonds between carbons and carbon-to-hydrogen bonds, the presence of at least one double bond makes the hydrocarbon unsaturated.

Therefore, first and second statements are correct.

Best regards.