The Total solution for NCERT class 6-12
The enthalpy of combustion of methane,graphite and dihydrogen at 298 K are, –890.3 kJ mol–1 –393.5 kJ mol–1, and –285.8 kJ mol–1 respectively.Enthalpy of formation of CH4(g) will be
(i) –74.8 kJ mol–1 (ii) –52.27 kJ mol–1
(iii) +74.8 kJ mol–1 (iv) +52.26 kJ mol–1.
According to the question,
Thus, the desired equation is the one thatrepresents the formation of CH4 (g) i.e.,
Enthalpy of formation of CH4(g) = –74.8 kJ mol–1
Hence,alternative (i) is correct.