Question

1. Two moist red roses are taken in two containers
A and B into which anhydride of sulphurous acid
and a greenish yellow coloured gas are passed,
respectively. What changes are observed with respect
to two roses in A and B? How do you account for
these changes?​

Answer 1

Answer:

In container A containing moist red rose, sulphur dioxide gas (anhydride of sulphurous acid) is passed. This leads to discolouration of the rose petals due to bleaching action of the gas. However, the effect is not strong and the colour of roses appears again after some time (on exposure to atmospheric oxygen).

In container B containing moist red rose, chlorine gas (greenish yellow gas) is passed. This gas also causes discolouration of the rose petals due to its bleaching action. However, the effect of chlorine is much stronger than sulphur dioxide and the rose petals are permanently bleached.