The number of 4f electrons in the ground statement electronic configuration of Gd²⁺ is ___________. [Atomic number of Gd = 64]

The ratio of number of water molecules in Mohr's salt and potash alum is ____________ $$\times$$ 10^$$-$$1. (Integer answer)

The following data was obtained for chemical reaction given below at 975 K.

2NO_(g) + 2H_2(g) $$\to$$ N_2(g) + 2H₂O_(g)



The order of the reaction with respect to NO is ___________. [Integer answer]

The Born-Haber cycle for KCl is evaluated with the following data :

$${\Delta _f}{H^\Theta }$$ for KCl = $$-$$436.7 kJ mol^$$-$$1 ;

$${\Delta _{sub}}{H^\Theta }$$ for K = 89.2 kJ mol^$$-$$1 ;

$${\Delta _{ionization}}{H^\Theta }$$ for K = 419.0 kJ mol^$$-$$1 ;

$${\Delta _{electron\,gain}}{H^\Theta }$$ for Cl_(g) = $$-$$348.6 kJ mol^$$-$$1 ;

$${\Delta _{bond}}{H^\Theta }$$ for Cl₂ = 243.0 kJ mol^$$-$$1

The magnitude of lattice enthalpy of KCl in kJ mol^$$-$$1 is _____________ (Nearest integer)