A coloured compound (A) reacts with dilute H2SO4 to produce a colourless gas (B) and colourless solution (C). The reaction between (B) and the acidified K2Cr2O7 solution produces a green solution and a slightly yellowish precipitate (D). The substance (D) burns in air to produce a gas (E) which also can change the colour of K2Cr2O7 solution.
When D is boiled with alkaline sulphite solution a compound F is formed. F can be used in
(I) Iodine titrations in volumetric analysis
(II) Bleaching industry to destroy excess Cl2
(III) Photography for 'fixing' films
(IV) Iodometric titrations
Choose the correct codes:
a. I and IV
b. I, III and IV
c. II and III
d. I, II, III and IV