Environmental Chemistry - Result Question 15
####15. The higher concentration of which gas in air can cause stiffness of flower buds?
(a) $SO _2$
(b) $CO$
(c) $CO _2$
(d) $NO _2$
(2019 Main, 11 Jan II)
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Answer:
Correct Answer: 15. (d)
Solution:
- Organic pigments (colourents) present in flower buds retain their colour in the oxidised form of the pigment as their nature is itself oxidising in nature. When they comes in contact with moist $SO _2$ (acid rain) of higher concentration, they get decoloured and stiff.
$$ \begin{aligned} SO _2+H _2 O & \longrightarrow H _2 SO _4 \ H _2 SO _4 & \longrightarrow H^{+}+HSO _4^{-} \ HSO _4^{-} & \longrightarrow H^{+}+SO _4^{2-} \end{aligned} $$
Due to the release of $H^{+}$ion (acid), the flower get decoloured and stiff.
As a result, flower eventually falls off from plants.
