Predict whether ΔS for each reaction would be greater than zero, less than zero, or too close to zero to decide.
ΔS > 0; ΔS < 0; too close to decide
I2(g) + Cl2(g) > 2ICl(g)
2NOBr(g) > 2NO(g) + Br2(g)
CO2(g) + H2(g) > CO(g) + H2O(g)
2H2O2(I) > 2H2O(I) + O2(g)

a) : too close to decide.

b) : > 0.

c) : too close to decide.

d)  : > 0.

Explanation:

Entropy is the measure of randomness or disorder of a system. If a system moves from  an ordered arrangement to a disordered arrangement, the entropy is said to decrease and vice versa.

For the reaction:

a)

In this reaction 2 moles of gaseous reactants are converting to 2 moles of gaseous products. Thus is too close to decide.

b)  

In this reaction 2 moles gaseous reactants is getting converted to 3 moles of gaseous products. Thus the randomness will increase and hence entropy will also increase.Thus > 0.

c)

In this reaction 2 moles of gaseous reactants are converting to 2 moles of gaseous products. Thus is too close to decide.

d)  

In this reaction 2 moles liquid reactants is getting converted to 2 moles of liquid and 1 mole of gaseous products. Thus the randomness will increase and hence entropy will also increase.Thus > 0.