Out of 2-chloroethanol and ethanol which is more acidic and why ?

Options

A. 2-Chloroethanol due to `+I` effect of Cl
B. Ethanol due to `+I` effect of `CH_(3)`
C. 2-Chloroehtanol due to `-I` effect of Cl
D. Ethanol due to `-I` effect of `CH_(3)`

Answer

To determine which compound is more acidic between 2-chloroethanol and ethanol, we need to analyze their structures and the effects of their substituents on acidity.

### Step 1: Identify the structures of the compounds
- **2-chloroethanol** has the formula CH2ClCH2OH.
- **Ethanol** has the formula CH3CH2OH.

### Step 2: Understand acidity in alcohols
Acidity in alcohols is primarily determined by the stability of the alkoxide ion (the conjugate base formed after deprotonation). The more stable the alkoxide ion, the stronger the acid.

### Step 3: Analyze the effect of substituents
- In **2-chloroethanol**, the chlorine atom is an electronegative element that exerts a negative inductive effect (-I effect). This means that chlorine pulls electron density away from the carbon chain, stabilizing the negative charge on the alkoxide ion (CH2ClCH2O⁻) when the hydrogen from the hydroxyl group is removed.
- In **ethanol**, there are no electronegative substituents to stabilize the alkoxide ion. Therefore, the negative charge on the alkoxide ion (CH3CH2O⁻) is less stabilized compared to that in 2-chloroethanol.

### Step 4: Compare the stability of the alkoxide ions
- The alkoxide ion from **2-chloroethanol** is more stable due to the -I effect of chlorine, which helps to delocalize the negative charge.
- The alkoxide ion from **ethanol** is less stable because it lacks any electronegative substituents to stabilize the negative charge.

### Step 5: Conclusion
Since the alkoxide ion from 2-chloroethanol is more stable than that from ethanol, we conclude that **2-chloroethanol is more acidic than ethanol**.

### Final Answer
2-chloroethanol is more acidic than ethanol due to the -I effect of the chlorine atom, which stabilizes the alkoxide ion formed after deprotonation.

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