Explain if change in entropy is positive-negative or zero

Question

Assuming the temperature is constant, predict whether the change in entropy (delta S) is positive, negative or zero during the followings reactions:

a.) Ni(s)+ Cl₂(g) ---> NiCl₂(s)

b.) NO₂(g) + N₂O(g) ----> 3NO(g)

c.) CH₃COOH(l) ----> CH₄₍g) + CO₂(g)