Which of the following statements is /are incorrect?

Options

A. A filter paper moistened with cadmium acetate solution turn yellow, when brought in contact with `H_(2)S` gas.
B. Both carbonate ions as well as bicarbonate ions in the solutions, give reddish-brown precipitate with mercury `(II)` chloride.
C. Sulphites in presence of zinc, reacts with dilute `H_(2)SO_(4)` to liberate `SO_(3)` gas.
D. A filter paper moistened with `KIO_(3)` and starch turns blue in contact with `SO_(2)` vapours.

Answer

B,C

Explanation

(A)`Cd^(2+)(aq)+H_(2)S(g)toCdSdarr("yellow ")+2H^(+)(aq)`
(B)`Co_(3)^(2-)+4Hg^(2+)+3H_(2)O to Hg_(4)O_(3)CO_(3)darr ("reddish-brown")+6H^(+)`
`HCO_(3)^(-) (aq)` does not give precipitate.
( C)`SO_(3)^(2-)+3Zn+8H^(+) to H_(2)S uarr 3Zn^(2-)+3H_(2)O`
(D )`5SO_(2)+2IO_(3)^(-)+4H_(2)OtoI_(2)+5SO_(4)^(2-)+8H^(+)`