Predict in which of the following , entropy increases or decreases .
(i) A liquid crystallizes into a solid
(ii)Temperature of a crystallized solid is raised from 0 K to 115 K
(iii)`2NaHCO_(3(s)) to Na_2CO_(3(s)) + CO_(2(g)) + H_2O_((g))`
(iv)`H_(2(g)) to 2H_((g))`

Explanation

(i)After freezing, the molecules attain an ordered state and therefore, entropy decreases.
(ii) At 0 K the constituent particles are in static form therefore, entropy is minimum. If the temperature is raised to 115 K particles begin to move and entropy increases
(iii) Reactant, `NaHCO_3` is solid, Thus, its entropy is less in comparison to product which has high entropy
(iv) Here, one molecule gives two atoms. Thus, number of particles increases and this leads to more disordered form.