2007 chem 急 mc

1. bromine water can oxidize sulphur dioxide and it becomes
decolourized. and calcium hydroxide can turn milky when
carbon dioxide pass through.
for c and d, the first part is correct , but the second is wrong.
sodium hydroxide will not turn milky when carbon dioxide
pass through.
2. concentrated sulphuric acid act as oxidizing agent only
in this reaction.

20.
solution Y must be calcium hydroxide (lime water) as it can indicate the presence of carbon dioxide by turning milky.
bromide water will be reduced and decolourized by SO2
So, the answer is A
21.
Statements (1) and (2) are correct.
Statement (3) is not correct as conc. sulphuric acid has not acted as dehydrating agent in this reaction as nothing has been dehydrated.
So, the answer is A