Question

One gas bleaches the colour of flowers by reduction while the other gas by oxidation. The two gases are, respectively:

• A. $CO$ & $C{l}_2$
• B. $H_{2}S$ & $B{r}_2$
• C. $S{O}_2$ & $C{l}_2$
• D. $N{H}_3$ & $S{O}_3$

Answer 1

The correct option is C $S{O}_2$ & $C{l}_2$

Sulphur dioxide and chlorine gas are the two gases that bleach the colour of flower by oxidation and reduction.

Chlorine reacts with water and produces a single oxygen atom also called nascent oxygen. This nascent oxygen when combines with any colour make it colourless.

$C{l}_2+H_{2}O\to 2HCl+\left(O\right)$ (O is oxidizing)

Sulphur dioxide when reacts with coloured substances it releases oxygen from the substance resulting in loss of colour.

$S{O}_2+2H_{2}O\to H_{2}S{O}_4+2\left(H\right)$ (H is reducing)

Hence, the correct option is $C$