Ketones are less reactive than aldehydes because

Options

A. The + I-effect of the alkyl groups increases the electron deficiency of the carbonyl carbon
B. The + I-effect of the alkyl groups decreases the electron deficiency of the carbonyl carbon
C. Of steric hindrance to the attacking nucleophile
D. Both (b) and (c) options are correct

Explanation

To understand why ketones are less reactive than aldehydes, we can break down the explanation into several steps:

### Step-by-Step Solution

1. **Understanding the Structure of Aldehydes and Ketones**:
- Aldehydes have the general structure RCHO, where R can be a hydrogen atom or an alkyl group.
- Ketones have the general structure R2C=O, where R represents alkyl groups.

2. **Electronegativity and Carbonyl Group**:
- In both aldehydes and ketones, the carbonyl group (C=O) is polar due to the electronegativity of oxygen, which creates a partial positive charge on the carbon atom (the carbonyl carbon) and a partial negative charge on the oxygen atom.

3. **Nucleophilic Attack**:
- Nucleophiles are electron-rich species that are attracted to the electron-deficient carbonyl carbon. The reactivity of carbonyl compounds in nucleophilic addition reactions depends on how electron-deficient the carbonyl carbon is.

4. **Effect of Alkyl Groups**:
- In ketones, the carbonyl carbon is bonded to two alkyl groups, which can donate electron density through the +I (inductive) effect. This electron donation reduces the electron deficiency of the carbonyl carbon, making it less reactive towards nucleophiles.
- In contrast, aldehydes have one hydrogen atom attached to the carbonyl carbon, which does not donate electron density as effectively as alkyl groups. Therefore, the carbonyl carbon in aldehydes is more electron-deficient and more reactive.

5. **Steric Hindrance**:
- Ketones have larger alkyl groups on both sides of the carbonyl carbon, which can create steric hindrance. This steric hindrance makes it more difficult for nucleophiles to approach and attack the carbonyl carbon compared to aldehydes, which have only one bulky group (the alkyl group) and one smaller hydrogen atom.

6. **Conclusion**:
- Combining the effects of electron donation from alkyl groups and steric hindrance, we conclude that ketones are less reactive than aldehydes due to:
- Greater electron donation from two alkyl groups in ketones, reducing the electron deficiency of the carbonyl carbon.
- Increased steric hindrance in ketones, making nucleophilic attack less favorable.