Explain the entropy concept and discuss the nature of change in entropy (increase or decrease) for `:`
(i) `H_(2)O(l) rarrH_(2)O(s)`
(ii) `MgCO_(3)(s) rarr MgO(s) + CO_(2)(g)`
(iii) `2SO_(2)(g) +O_(2)(g) rarr 2SO_(3)(g)`

For the system S (s) + O_(2)(g) rarr SO_(2)(g) ?

Assign the sign of work done (based on SI convention) in the following chemical change taking place against external atmospheric pressure. (i) N_(2)O_(3)(g)rarr NO(g)+NO_(2)(g) (ii) MgCO_(3)(g)rarr MgO(s)+CO_(2)(g) (iii) C_(6)H_(6)(l)+(15)/(2)O_(2)(g)rarr 6CO_(2)(g)+3H_(2)O(l) (iv) 3H_(2)(g)+N_(2)(g)rarr 2NH_(3)(g) (v) N_(2)O_(4)(g)rarr 2NO_(2)(g) (vi) 2Fe_(2)O_(3)(s)+6CO(g)rarr 4Fe(s)+6CO_(2)(g)

Delta S for the reaction , MgCO_(3)(s)rarr MgO(s)+CO_(2)(g) will be :

For each reaction, wheter the sign of Delta S (entropy) is positive or negative ? (a) Ni(s)+4CO(g)rarr Ni(CO)_(4)(g) (b) 4Fe(s)+3O_(2)(g)rarr 2Fe_(2)O(s) (c ) H_(2)(g)+S(s)rarr H_(2)S(g) (d) 2NO(g)+O_(2)(g)rarr 2NO_(2)(g)

What conclusion can be drawn from the following reactions about the nature of oxides? (1) 4Na(s) + O_2(g)rarr 2Na_(2)O(s); Na_(2)O(s) + H_(2)O(l) rarr 2NaOH(aq) (2) S(s) + O_2(g)rarr SO_(2)(g); SO_(2)(g) + H_(2)O(l) rarr H_(2)SO_(4)(aq)