Which of the following is a natural polymer? MCQ with Answer and Explanation

Explanation:
In the Contact process, the key catalytic step is oxidation of SO₂ to SO₃ using V₂O₅ (vanadium pentoxide) catalyst at 450°C: 2SO₂ + O₂ ⇌ 2SO₃. Sulfur burning is non-catalytic. The SO₃ is absorbed in 98% H₂SO₄ to form oleum (H₂S₂O₇), then diluted to get concentrated H₂SO₄. Direct dissolution of SO₃ in water is avoided due to mist formation.

Explanation:
Ant sting contains formic acid (methanoic acid, HCOOH), causing irritation. Nettle sting also contains formic acid. To neutralize, apply a base like baking soda. Acetic acid is in vinegar, citric acid in citrus fruits, lactic acid in sour milk and muscles. Formic acid is the simplest carboxylic acid.

Explanation:
Alpha particles (α) are positively charged particles consisting of two protons and two neutrons, identical to the nucleus of a helium-4 atom (He²⁺). They are emitted during alpha decay of heavy radioactive elements like uranium and radium.