If a compound is reduced, what is the result?
Fewer C-H bonds
Increased number of C-H bonds
Fewer C-Z bonds
Both increased number of C-H bonds and fewer C-Z bonds
The correct answer and explanation is :
Correct Answer:
Both increased number of C-H bonds and fewer C-Z bonds
Explanation:
Reduction in organic chemistry refers to the gain of electrons by a molecule, which often corresponds to an increase in the number of hydrogen (H) atoms or a decrease in the number of bonds to more electronegative atoms (such as oxygen, nitrogen, or halogens, represented as Z).
- Increase in C-H Bonds
- Reduction commonly involves the addition of hydrogen atoms to a carbon framework.
- For example, the reduction of an alkene (C=C) to an alkane (C-C) using hydrogen gas and a catalyst (e.g., H₂/Pd) results in an increase in the number of C-H bonds.
- Similarly, the reduction of a ketone (C=O) to an alcohol (C-OH) involves the addition of hydrogen, increasing the number of C-H bonds on the formerly carbonyl carbon.
- Decrease in C-Z Bonds
- Reduction also decreases the number of bonds between carbon and more electronegative atoms (Z), such as oxygen, nitrogen, or halogens.
- For example, the reduction of a carboxylic acid (R-COOH) to an aldehyde (R-CHO) or an alcohol (R-CH₂OH) removes C=O bonds, replacing them with C-H or C-OH bonds.
- The same concept applies to halogenated compounds where reduction (e.g., Zn/HCl) removes halogen atoms, leading to fewer C-Z bonds.
Thus, reduction generally leads to both an increase in C-H bonds and a decrease in C-Z bonds, making the correct answer “Both increased number of C-H bonds and fewer C-Z bonds.”