Acids and Bases

Question 1

Monoprotic vs Polyprotic Acids

Answer 1

A monoprotic acid can donate only one proton per molecule, as in HCl or acetic acid, whereas a polyprotic acid can release two or more, such as H₂SO₄ or H₃PO₄. Successive deprotonations of polyprotic acids become less favourable, giving multiple, progressively smaller acid dissociation constants. Polyprotic behaviour shapes the distinct buffering regions on titration curves.

Question 2

Amphoteric Substances

Answer 2

Amphoteric substances can act either as an acid or a base depending on the reaction partner. Water and aluminium hydroxide are classic examples: they donate a proton to stronger bases yet accept one from strong acids. This duality arises from the presence of both acidic hydrogen and basic lone pairs or hydroxide centres.

Question 3

Four Main Macromolecules

Answer 3

Carbohydrates are sugar polymers that store quick energy and lend structural support (cellulose). Lipids are hydrophobic molecules—fats, oils, phospholipids—that store long‑term energy and form membranes. Proteins made of amino acids act as catalysts, motors, and structural frameworks, while nucleic acids (DNA, RNA) encode and transmit genetic information.