Question

The standard enthalphy of formation of NH3
is -46.0 kJ mol-1. If the enthalpy of formation of
H2 from its atoms is -436 kJ mol-1 and that of N2
is - 712kJ mol-1, the average bond enthalpy of
N-H bond in NH3 is :-
(1) -1102 kJ mol-1
(2) -964 kJ mol-1
(3) + 352 kJ mol-1
(4) +1056 kJ mol-1​

Answer 1

The standard enthalphy of formation of NH3

is -46.0 kJ mol-1. If the enthalpy of formation of

H2 from its atoms is -436 kJ mol-1 and that of N2

is - 712kJ mol-1, the average bond enthalpy of

N-H bond in NH3 is :-

(1) -1102 kJ mol-1

(2) -964 kJ mol-1

(3) + 352 kJ mol-1

(4) +1056 kJ mol-1✔️✔️✔️