Question

The higher concentration of which gas in air can cause stiffness of flower buds?
1. SO₂
2. CO
3. CO₂
4. NO₂

Answer 1

Correct Answer - Option 1 : SO₂

Concept:

Organic pigments (colorants) present in flower buds retain colour in the oxidized form of the pigment as our nature is itself oxidizing in nature. When they come in contact with moist SO₂ (acid rain) of higher concentration, they get decoloured and stiff.

SO₂ + H₂O → H₂SO₄

\({H_2}S{O_4} \to {H^ + } + HSO_4^ -\)

\(HSO_4^ - \to {H^ + } + SO_4^{2 - }\)

Due to the release of H⁺ ion (acid), the flower gets decoloured and stiff. As a result, flower eventually falls off from plants.