When dry chlorine gas is passed over molten white phosphorus, a mixture of wo chlorides (phosphorus trichloride and phosphorus pentachloride) is obtained. The hosphorus gives phosphorus trichloride with limited supply of chlorine and hosphorus pentachloride with excess chlorine …?

Answer 1

When dry chlorine gas is passed over molten white phosphorus (P₄), different reactions take place depending on the amount of chlorine available:

1. Limited Supply of Chlorine:

   • When there is a limited supply of chlorine gas, phosphorus primarily reacts to form phosphorus trichloride (PCl₃). The reaction can be represented as follows: \[ P_4 + 6Cl_2 \rightarrow 4PCl_3 \]
   • This reaction occurs due to the availability of chlorine being insufficient to convert all phosphorus into phosphorus pentachloride.

2. Excess Supply of Chlorine:

   • When chlorine is supplied in excess, phosphorus can be fully chlorinated to form phosphorus pentachloride (PCl₅). The reaction in this case can be represented as: \[ P_4 + 10Cl_2 \rightarrow 4PCl_5 \]
   • Here, the excess chlorine allows all the phosphorus to react completely, resulting in the formation of phosphorus pentachloride.

Summary: The products depend on the amount of chlorine gas available:

• Limited chlorine → Phosphorus trichloride (PCl₃)
• Excess chlorine → Phosphorus pentachloride (PCl₅)