Which of the following molecules shows an appropriate number of bonds around each carbon atom, following the octet rule?

• A. $C_3{H}_8$ with a carbon having five bonds
• B. $C_2{H}_2$ with a carbon having only two bonds
• C. $C_2{H}_5$
• D. $C_2{H}_6$ (ethane)

Answer: (D)

Verified step by step guidance

1. Recall that carbon atoms typically follow the octet rule, meaning each carbon should form four covalent bonds to complete its valence shell.
2. Examine the first molecule, C\_3H\_8, and identify if any carbon atom has more than four bonds. A carbon with five bonds violates the octet rule, so this molecule is not appropriate in that context.
3. Look at the second molecule, C\_2H\_2, and check if any carbon has fewer than four bonds. A carbon with only two bonds does not satisfy the octet rule, indicating an incomplete valence shell.
4. Consider the third molecule, C\_2H\_5, and count the bonds around each carbon. If any carbon does not have four bonds, it does not follow the octet rule properly.
5. Finally, analyze C\_2H\_6 (ethane). Each carbon in ethane forms four single bonds (three with hydrogens and one with the other carbon), satisfying the octet rule and making it the correct molecule with an appropriate number of bonds around each carbon.