when dry chlorine gas is passed over molten White Phosphorus a mixture of two chloride Phosphorus trichloride and phosphorus pentachloride is obtained the Phosphorus gives Phosphorus trichloride with Limited supply of chlorine and phosphorus pentachloride with excess chlorine.

Question

when dry chlorine gas is passed over molten  White Phosphorus a mixture of two chloride Phosphorus trichloride and phosphorus pentachloride is obtained the Phosphorus gives Phosphorus trichloride with Limited supply of chlorine and phosphorus pentachloride with excess chlorine. 
Give details of this question and write the Rxn by the expression of  Lewis dot structure

GPT-4o mini · Answer

When dry chlorine gas ($Cl_2$) is passed over molten white phosphorus ($P_4$), two different chlorinated phosphorus compounds can be formed depending on the amount of chlorine supplied in the reaction. 1. **Phosphorus Trichloride ($PCl_3$)**: This compound is formed when white phosphorus reacts with a limited supply of chlorine. The reaction can be expressed as: $$ P_4(s) + 6Cl_2(g) \rightarrow 4PCl_3(l) $$ In this reaction, one molecule of white phosphorus ($P_4$) reacts with six molecules of chlorine to produce four molecules of phosphorus trichloride. 2. **Phosphorus Pentachloride ($PCl_5$)**: This compound is produced when there is an excess of chlorine present during the reaction. The equation for this reaction is: $$ P_4(s) + 8Cl_2(g) \rightarrow 4PCl_5(s) $$ Here, one molecule of white phosphorus reacts with eight molecules of chlorine to yield four molecules of phosphorus pentachloride. ### Lewis Dot Structures 1. **Lewis Dot Structure for $PCl_3$**: - Phosphorus has five valence electrons and can form three covalent bonds with chlorine, resulting in a trigonal pyramidal structure. - Each chlorine atom contributes one electron to form a single bond with phosphorus. The remaining lone pairs are depicted around each chlorine. $$ \text{Lewis Structure of } PCl_3: $$ ``` Cl | P - Cl | Cl ``` Here, the phosphorus atom is the central atom bonded to three chlorine atoms, each of which has three lone pairs of electrons. 2. **Lewis Dot Structure for $PCl_5$**: - In phosphorus pentachloride, phosphorus expands its octet and forms five bonds with chlorine atoms. $$ \text{Lewis Structure of } PCl_5: $$ ``` Cl | Cl - P - Cl | | Cl Cl ``` In this structure, phosphorus is at the center bonded to five chlorine atoms. Each chlorine has three lone pairs. ### Summary: - **PCl₃** is formed by limited chlorine and has a trigonal pyramidal shape. - **PCl₅** is formed by excess chlorine and has a trigonal bipyramidal shape. - Both reactions involve the formation of covalent bonds between phosphorus and chlorine, with the structures indicating the connectivity and electron distribution around each atom.