For which of the reactions listed below will Gibbs free energy always be negative?

A. An exothermic reaction that increases in entropy
B. An endothermic reaction that decreases in entropy
C. An endothermic reaction that increases in entropy
D. An exothermic reaction that decreases in entropy

Isn't that A?

dG = dH - TdS.
If dH is - and dS is +, then -TdS will be negative; thus dG will ALWAYS be negative.

It's A

I did this question for my ap chemistry class and the correct answer is A.

To determine for which of the reactions listed below Gibbs free energy will always be negative, we need to consider the equation for Gibbs free energy (ΔG = ΔH - TΔS), where ΔG is the change in Gibbs free energy, ΔH is the change in enthalpy, ΔS is the change in entropy, and T is the temperature in Kelvin.

Let's analyze each option:

A. An exothermic reaction that increases in entropy: In this case, ΔH will be negative because it's an exothermic reaction. If ΔS is positive, which means that the entropy increases, then TΔS will also be positive. Since both TΔS and ΔH are negative, their sum (ΔG) will likely be negative. Thus, option A is a possibility.

B. An endothermic reaction that decreases in entropy: In this case, ΔH will be positive because it's an endothermic reaction. If ΔS is negative, which means that the entropy decreases, then TΔS will be negative. Since ΔH is positive and TΔS is negative, their sum (ΔG) will likely be positive. Thus, option B is unlikely.

C. An endothermic reaction that increases in entropy: In this case, ΔH will be positive because it's an endothermic reaction. If ΔS is positive, which means that the entropy increases, then TΔS will also be positive. Since both ΔH and TΔS are positive, their sum (ΔG) will likely be positive. Thus, option C is unlikely.

D. An exothermic reaction that decreases in entropy: In this case, ΔH will be negative because it's an exothermic reaction. If ΔS is negative, which means that the entropy decreases, then TΔS will be negative. Since both ΔH and TΔS are negative, their sum (ΔG) will likely be negative. Thus, option D is a possibility.

Based on this analysis, options A and D are the most likely to have a negative ΔG, depending on the specific values of ΔH and ΔS.

it's actually endothermic reaction that decreases in entropy.