The bond dissociation energy of B - F in BF₃ is 646 kJ mol^-1 whereas that of C - F in CF₄ is 515 kj mol^-1. The correct reason for higher B - F bond dissociation energy as compared to that of C - F is

Which of the following pair of species have the same bond order?

Oxidising power of chlorine in aqueous solution can be determined by the parameters indicated below:
$${1 \over 2}C{l_2}(g)$$ $$\buildrel {{1 \over 2}{\Delta _{diss}}{H^\Theta }} \over \longrightarrow $$ $$Cl(g)$$ $$\buildrel {{\Delta _{eg}}{H^\Theta }} \over \longrightarrow $$ $$C{l^ - }(g)$$ $$\buildrel {{\Delta _{Hyd}}{H^\Theta }} \over \longrightarrow $$ $$C{l^ - }(aq)$$
(Using the data, $${\Delta _{diss}}H_{C{l_2}}^\Theta $$ = 240 kJ/mol, $${\Delta _{eg}}H_{Cl}^\Theta $$ = -349 kJ/mol, $${\Delta _{hyd}}H_{C{l^ - }}^\Theta $$ = - 381 kJ/mol) will be :

Standard entropy of X₂, Y₂ and XY₃ are 60, 40 and 50 JK⁻¹ mol⁻¹ , respectively. For the reaction,
$${1 \over 2} X_2$$ + $${3 \over 2} Y_2 \to$$ XY₃, $$\Delta H$$ = -30 kJ, to be at equilibrium, the temperature will be :