Arrange these reactions according to increasing ΔS. a. H 2O(g) → H 2O(l)
b. 2NO(g) → N 2(g) + O 2(g)
C. MgCO 3(s) → MgO(s) + CO2(g)

Explanation:

ΔS denotes change in entropy. Entropy is the degree of disorderliness of a system. An increasing ΔS would mean that the entropy of the products is greater than the entropy of the reactants.

Generally the trend of entropy with state of matter is given as;

Gas > Liquid > Solid (Increasing Entropy)

a. H 2O(g) → H 2O(l)

In this reaction, there is a decreasing ΔS, since we are moving from gas to liquid. This would be the last.

b. 2NO(g) → N 2(g) + O 2(g)

There is an increase in gaseous products. This is definitely an increasing ΔS reaction. This would be the first on the list.

C. MgCO 3(s) → MgO(s) + CO2(g)

The products formed are in solid and gaseous state. There is increasing ΔS but not up to reaction 2.

The order is given as;

b. 2NO(g) → N 2(g) + O 2(g)

C. MgCO 3(s) → MgO(s) + CO2(g)

a. H 2O(g) → H 2O(l)