G The reaction C(s) + CO2(g) → 2CO(g) is spontaneous only at temperatures in excess of 1100 K. We can conclude that a. ΔG° is negative for all temperatures. b. ΔH° is negative and ΔS° is negative. c. ΔH° is positive and ΔS° is positive. d. ΔH° is negative and ΔS° is positive. e. ΔH° is positive and ΔS° is negative.

c. ΔH° is positive and ΔS° is positive.

Explanation:

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In this case, as the Gibbs free energy for a reaction is defined in terms of the change in the enthalpy and entropy as shown below:

Thus, as the reaction becomes spontaneous (ΔG°<0) at temperatures above 1100K (high temperatures), it necessary that c. ΔH° is positive and ΔS° is positive as the entropy will drive the spontaneousness as it becomes smaller than TΔS°.

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