AX is a covalent diatomic molecule where A and X are second row elements of periodic table. Based on Molecular orbital theory, the bond order of AX is 2.5. The total number of electrons in AX is __________. (Round off to the Nearest Integer).

In order to prepare a buffer solution of pH 5.74, sodium acetate is added to acetic acid. If the concentration of acetic acid in the buffer is 1.0 M, the concentration of sodium acetate in the buffer is ___________ M. (Round off to the Nearest Integer). [Given : pKa (acetic acid) = 4.74]

2NO(g) + Cl₂(g) $$\rightleftharpoons $$ 2NOCl(s)

This reaction was studied at $$-$$10$$^\circ$$ and the following data was obtained

Run	$${[NO]_0}$$	$${[C{l_2}]_0}$$	$${r_0}$$
1	0.10	0.10	0.18
2	0.10	0.20	0.35
3	0.20	0.20	1.40

$${[NO]_0}$$ and $${[C{l_2}]_0}$$ are the initial concentrations and r₀ is the initial reaction rate.

The overall order of the reaction is __________. (Round off to the Nearest Integer).

For the reaction C₂H₆ $$ \to $$ C₂H₄ + H₂

the reaction enthalpy $$\Delta$$_rH = __________ kJ mol^$$-$$1. (Round off to the Nearest Integer).

[ Given : Bond enthalpies in kJ mol^$$-$$1 : C-C : 347, C = C : 611; C-H : 414, H-H : 436 ]