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)
