1.1 Nature and Definitions of Acids and Bases

What are the general properties of acids and bases?

Acids have a sour taste, dissolve metals, neutralize bases, and turn blue litmus red. Bases are bitter, slippery, neutralize acids, and turn red litmus blue.

What is the Arrhenius definition of an acid?

An acid is a substance that produces H+ ions in solution.

What is the Brønsted–Lowry definition of a base?

A base is a proton acceptor that contains a lone pair or can bond with H+.

What is a conjugate acid–base pair?

A conjugate acid–base pair consists of two substances related by the gain or loss of a proton.

What does it mean for a substance to be amphoteric?

Amphoteric substances can act as either an acid or a base depending on the reaction.

Give an example of an oxyacid.

HNO₃ (Nitric acid) or H₂SO₄ (Sulfuric acid).

What distinguishes strong acids from weak acids?

Strong acids ionize completely (Ka >> 1) and produce a weak conjugate base, while weak acids ionize only slightly (Ka << 1) and have a stronger conjugate base.

What is the significance of the Ka value?

Ka is the equilibrium constant for acid ionization, measuring acid strength in reaction with water. Large Ka indicates a strong acid, while small Ka indicates a weak acid.

How does the equilibrium position differ between strong acids and weak acids?

For strong acids, the equilibrium position lies far to the right, while for weak acids, it favors the reactants.

What is the relationship between the strength of an acid and its conjugate base?

The stronger the acid, the weaker its conjugate base; the weaker the acid, the stronger its conjugate base.

What factors influence acid strength in terms of ionic attraction?

Acid strength depends on bond polarity (more polar H–X bond → stronger acid) and bond strength (weaker H–X bond → stronger acid).