Introduction:

Sandmeyer's reaction is a chemical reaction that is used to replace the -NH2 or -NR2 group of an aromatic amine with other functional groups such as -Br, -Cl, -F, or -CN, etc. Cu2Cl2 is used as a reagent in Sandmeyer's reaction instead of CuCl2 due to some specific reasons.

Cu2Cl2 vs CuCl2:

Cu2Cl2 is preferred over CuCl2 due to the following reasons:

1. Stability:

Cu2Cl2 is more stable than CuCl2. It is because Cu2Cl2 has a dimeric structure, while CuCl2 has a monomeric structure. The dimeric structure of Cu2Cl2 makes it more stable than CuCl2.

2. Solubility:

Cu2Cl2 is less soluble in water than CuCl2. It is because the dimeric structure of Cu2Cl2 makes it less soluble in water. The low solubility of Cu2Cl2 makes it easier to handle in Sandmeyer's reaction.

3. Reactivity:

Cu2Cl2 is less reactive than CuCl2. It is because the dimeric structure of Cu2Cl2 makes it less reactive than CuCl2. The low reactivity of Cu2Cl2 makes it less likely to cause unwanted side reactions in Sandmeyer's reaction.

Conclusion:

Cu2Cl2 is used as a reagent in Sandmeyer's reaction instead of CuCl2 due to its stability, solubility, and reactivity. Cu2Cl2 is more stable, less soluble, and less reactive than CuCl2, which makes it a better choice for Sandmeyer's reaction.