Cuprous chloride can not be prepared :

Options

A. by passing `SO_2` through the solution containing `CuSO_4` and NaCl
B. by heating excess of copper with conc. HCl in presence of a little `KClO_3`
C. by boiling copper sulphate solution with excess of copper turnings in presence of hydrochloric acid
D. by dissolving cupric oxide or copper carbonate in HCl

Explanation

To determine from which reaction cuprous chloride (Cu2Cl2) cannot be prepared, we will analyze each of the provided reactions step by step.

### Step 1: Understanding Cuprous Chloride
Cuprous chloride is represented as Cu2Cl2. It is important to understand that we need to identify the reaction that does not yield this compound.

### Step 2: Analyzing the First Reaction
The first reaction states:
- **By passing SO2 through a solution containing CuSO4 and NaCl.**

The reaction can be represented as:
\[ \text{CuSO}_4 + \text{NaCl} + \text{SO}_2 \rightarrow \text{Cu}_2\text{Cl}_2 + \text{Na}_2\text{SO}_4 \]

This reaction proceeds and produces cuprous chloride (Cu2Cl2). Therefore, this method can prepare cuprous chloride.

### Step 3: Analyzing the Second Reaction
The second reaction states:
- **By heating excess copper with concentrated HCl in the presence of a little KClO3.**

The reaction can be represented as:
\[ \text{Cu} + \text{HCl} + \text{KClO}_3 \rightarrow \text{CuCl}_2 + \text{H}_2\text{O} \]

Since excess copper can react with CuCl2 to produce Cu2Cl2:
\[ \text{CuCl}_2 + \text{Cu} \rightarrow \text{Cu}_2\text{Cl}_2 \]

Thus, this reaction can also prepare cuprous chloride.

### Step 4: Analyzing the Third Reaction
The third reaction states:
- **By boiling copper sulfate solution with excess copper turnings in the presence of hydrochloric acid.**

The reaction can be represented as:
\[ \text{CuSO}_4 + \text{HCl} \rightarrow \text{CuCl}_2 + \text{H}_2\text{SO}_4 \]

Again, using excess copper:
\[ \text{CuCl}_2 + \text{Cu} \rightarrow \text{Cu}_2\text{Cl}_2 \]

This reaction can also prepare cuprous chloride.

### Step 5: Analyzing the Fourth Reaction
The fourth reaction states:
- **By dissolving cupric oxide or copper carbonate in HCl.**

For cupric oxide (CuO):
\[ \text{CuO} + 2\text{HCl} \rightarrow \text{CuCl}_2 + \text{H}_2\text{O} \]

For copper carbonate (CuCO3):
\[ \text{CuCO}_3 + 2\text{HCl} \rightarrow \text{CuCl}_2 + \text{H}_2\text{O} + \text{CO}_2 \]

In both cases, we only obtain CuCl2 and do not have any excess copper to convert it to Cu2Cl2. Therefore, cuprous chloride (Cu2Cl2) cannot be prepared from this reaction.

### Final Answer
Cuprous chloride cannot be prepared by:
**D. By dissolving cupric oxide or copper carbonate in HCl.**

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