Justify the following statements.
i. Water mixed with formic acid cannot be separated by fractional distillation.
ii. o -nitrophenol is steam volatile while p-nitrophenol is not.
iii. Freshly prepared FeSO_4 solution is insisted during the test for nitrogen in Lassaignes test.
iv. Copper spiral is used in the apparatus for Dumas method.

a) Identify redox reaction from the following reactions. i) Evaporation of water. ii) Conversion of oxygen to ozone in the upper atmosphere. iii) Formation of nitric oxide from nitrogen and oxygen during lightning. iv) Reaction of 'NaOH' with 'H_2 SO_4' b) Balance the following equation by oxidation number method. 'Fe^(2+)+Cr_2 O_7^(2-)+H^+ rarr F e^(3+)+Cr^(3+)+H_2 O'

Compare List-I and List-II and choose the correct matching codes from the choices given. {:(,"List-I",,"List-II"),("A.","Glycerol","(i)","Sublimation"),("B.","O-nitrophenol","(ii)","Beilstein's test"),("C.","Anthracene","(iii)","Victor-Meyer's method"),("D.","Halogens","(iv)","Steam distillation"),("E.","Molecular weight","(v)","Vacuum distillation"),(,,"(vi)","Eudiometry"):}