Which reaction shows that the enthalpy of formation of cs2 is hf = 89.4 kj/mol?

Note: Above question is incomplete.

Following is complete question:

Which reaction shows that the enthalpy of formation of CS2 is Hf = 89.4 kJ/mol?

A. C (s) + 2S (s) - - - > CS2 (l)

B. C (s) + 2S (s) - - - > CS2 (l) + 89.4 kJ

C. C (s) + 2S (s) + 89.4 kJ - - - > CS2 (l)

D. C (s) + 2S (s) + 89.4 kJ - - - > CS2 (l) + 89.4 kJ

...

Solution:

When one mole of a substance in the standard state is formed from its pure elements under the same conditions is called as enthalpy of formation.

In the above reaction, one mol of carbon and two mole of sulphur combines to form one mol of CS2. To carry out above reaction, an energy of 89.4 kJ/mol is to be supplied to the reaction system. This is evitable from positive value of heat of formation.

Hence, correct representation of reaction is option C i. e. C (s) + 2S (s) + 89.4 kJ → CS2 (l)