Answer:
Endothermic
Explanation:
An endothermic reaction is one in which energy is absorbed while an exothermic reaction is one in which energy is given out(evolved).
If we look at the reaction as written; 3C(graphite) + 3H2(g) + 88kcal -------> C3H8(g), we will notice that;
i) 88kcal of energy had to be absorbed for the reaction to occur
ii) The enthalpy change for the reaction is positive.
Since energy must be taken in to drive the forward reaction, then the reaction is endothermic as written.
