Order of reactivity of hydrogen halides towards ethers is

Options

A. `HCl gt HBr gt HI`
B. `HI gt HBr gt HCl`
C. `HBr gt HI gt HCl`
D. `HBr gt HCl gt HI`

Answer

To determine the order of reactivity of hydrogen halides (HX) towards ethers (ROR), we need to analyze how these hydrogen halides interact with ethers and the factors that influence their reactivity.

### Step-by-Step Solution:

1. **Identify the Ether Structure**:
- Ethers have the general structure ROR, where R represents an alkyl group.

2. **Reaction with Hydrogen Halides**:
- When an ether reacts with a hydrogen halide (HX), the ether bond (C-O) breaks. This leads to the formation of an alkyl halide (R-X) and an alcohol (R-OH).
- The reaction can be represented as:
\[ ROR + HX \rightarrow R-X + R-OH \]

3. **Consider the Halides**:
- The hydrogen halides we are considering are HCl, HBr, and HI.

4. **Analyze the Bond Strength and Size**:
- The reactivity of hydrogen halides towards ethers is influenced by the strength of the H-X bond and the size of the halide ion (X).
- As you move down the group in the periodic table from chlorine to iodine, the size of the halide ion increases (Cl < Br < I).

5. **Reactivity Trend**:
- Larger halide ions (like I-) are better at stabilizing the transition state during the reaction, which makes the bond cleavage easier and faster.
- Therefore, HI will react more readily with ethers than HBr, and HBr will react more readily than HCl.

6. **Establish the Order of Reactivity**:
- Based on the above analysis, the order of reactivity of hydrogen halides towards ethers is:
\[ HI > HBr > HCl \]

### Final Answer:
The order of reactivity of hydrogen halides towards ethers is:
\[ \text{HI} > \text{HBr} > \text{HCl} \]