KVPY SX SB Exam 2015 Question Paper

For the reaction ${\mathit{N}}_2+3{\mathit{X}}_2\to 2\mathit{N}{\mathit{X}}_3$ where X = F, Cl (the average bond energies are F-F = 155 kJ mol${}^{\mathit{–}1}$ N-F = 272 kJ mol${}^{\mathit{–}1}$ , Cl-Cl = 242 kJ mol${}^{\mathit{–}1}$ , N-Cl = 200 kJ mol${}^{\mathit{–}1}$ and N ≡ N = 941 kJ mol${}^{\mathit{–}1}$ ), the heats of formation of NF${}_3$ and NCl${}_3$ in kJ mol${}^{\mathit{–}1}$ , respectively, are closest to