⇒ degree of randomness of H2O molecules decreases, when freezing of water into ice takes place, ⇒∆S<0 (c) With increase in temperature, KE of H2O molecules of ice also increase. So, ∆S>0.
(d) 2NaHCO3(s)⟶Na2CO3(s)+CO2(g)+H2O(s)
Here, ∆ng>0⇒∆S>0 So, entropy decreases when liquid water crystallises into ice.