Select the correct answer.

A three-carbon alkene contains two double bonds. Predict its molecular formula.

A. [tex]\( C_3H_4 \)[/tex]

B. [tex]\( C_3H_5 \)[/tex]

C. [tex]\( C_3H_6 \)[/tex]



Answer :

To determine the correct molecular formula for a three-carbon alkene with two double bonds, let's follow the steps:

1. Identify the General Formula for Alkenes:
Alkenes are hydrocarbons with at least one double bond. The general formula for an alkene with one double bond is [tex]\(C_nH_{2n}\)[/tex].

2. Apply the General Formula for a Three-Carbon Alkene (One Double Bond):
If we have three carbons ([tex]\(n = 3\)[/tex]), the formula for a three-carbon alkene with one double bond is:
[tex]\[ C_3H_{2(3)} = C_3H_6 \][/tex]

3. Consider the Impact of Additional Double Bonds:
Each additional double bond in the alkene will reduce the number of hydrogen atoms by 2.

4. Calculate the Number of Hydrogens for a Three-Carbon Alkene with Two Double Bonds:
Starting with [tex]\(C_3H_6\)[/tex], one additional double bond will reduce the number of hydrogen atoms by 2. Therefore:
[tex]\[ C_3H_6 - 2H = C_3H_4 \][/tex]

So, the molecular formula for a three-carbon alkene with two double bonds is [tex]\(C_3H_4\)[/tex].

Therefore, the correct answer is:

A. [tex]\(\mathbf{C_3H_4}\)[/tex]