Which of the following four processes are accompanied by an increase in entropy?

Question

1. I2 (s) -> I2 (g)

2. 2 I (g) -> I2 (g)

3. 2 NH3 (g) -> N2 (g) + 3 H2 (g)

4. Pb2+ (aq) + 2 OH – (aq) -> Pb(OH)2 (s)

Answers: a. 1 & 2 b. 1 & 3 c. 3 & 4 d. 2 & 4 e. only 3

I am pretty sure that I2(s) -> I2(g) is an increase because it is going from a solid to a gas which has the highest entropy. As you can see there is not an answer choice for only choice 1 so I think that choice 2 might be an increase as well but I am not sure.

Would you agree that 2I(g) -> I2(g) is increasing?

Answer 1

I think that 2NH3(g) -> N2(g) + 3H2(g) is actually the other answer that is increasing because the number of moles increases from 2 to 4. So I chose answers 1 and 3. Is this correct?

Answer 2

1 and 3 are correct. Note that 2I^- --> I2 you are decreasing entropy.

Answer 3

Thank you!