The compound CH₄ is named: MCQ with Answer and Explanation

Explanation:
Calcium (Ca²⁺) and magnesium (Mg²⁺) ions react with soap anions to form insoluble precipitates (scum), preventing lather. Sodium and potassium soaps are soluble and lather well. So detergents are preferred in hard water because their calcium/magnesium salts are soluble. Hardness is measured in terms of CaCO₃ equivalent.

Explanation:
Decomposition of H₂O₂ yields water and O₂. It is catalyzed by MnO₂, light, or enzyme catalase. It's a disproportionation reaction.

Explanation:
Amylase (present in saliva and pancreatic juice) hydrolyses starch into maltose and dextrins. Pepsin digests proteins in the stomach. Lipase breaks down fats. Trypsin also digests proteins. Enzymes are specific biocatalysts.