Most Important Selected Qs for JEE AdvancedChemistryThermodynamics (C)
Paragraph: Enthalpy change for a chemical reaction can be calculated from bond enthalpy data. Bond enthalpy depends upon structural environment of the bond. From the data given below, answer the questions that follow. H _t [ PCl ₃( ~g ) ]=-320 ~kJ ~mol ⁻¹ ; H _ t [ P ( g )]=315 ~kJ ~mol ⁻¹ and H _t [ PCl ₅( ~g ) ]=-400 ~kJ ~mol ⁻¹ Question: Calculate bond enthalpy of P - Cl bond in PCl ₃ if enthalpy of atomisation of
Options
- A331.67 ~kJ ~mol ⁻¹
- B240.46 ~kJ ~mol ⁻¹
- C160.20 ~kJ ~mol ⁻¹
- D305.80 ~kJ ~mol ⁻¹
Correct answer
A. 331.67 ~kJ ~mol ⁻¹
Step-by-step solution
aligned & PCl ₃( ~g ) P ( g )+3 Cl ( g ) & 3 H _ P - Cl =315+3 120-(-320)=995 & H _ P - Cl =331.67 ~kJ ~mol ⁻¹ aligned