Pepsin is an enzyme that digests: MCQ with Answer and Explanation

Explanation:
Soap (sodium/potassium salts of long-chain fatty acids) reacts with Ca²⁺ and Mg²⁺ ions in hard water to form insoluble calcium/magnesium salts (scum), which precipitates and does not lather. This wastes soap. Reaction: 2RCOONa + Ca²⁺ → (RCOO)₂Ca↓ + 2Na⁺. Detergents do not form scum because their calcium salts are soluble. Hardness is measured in ppm of CaCO₃.

Explanation:
1/4 = (1/2)², so 2 half-lives = 40 days → half-life = 20 days. After 1 half-life 1/2 remains, after 2 half-lives 1/4.

Explanation:
James Chadwick discovered the neutron in 1932. He bombarded beryllium with alpha particles and observed a highly penetrating, neutral radiation, which he identified as neutrons. This discovery explained isotopes and completed the basic picture of the atom's subatomic particles.