Lecture 2 – Properties of Acids

Properties of Acids:

1. Acids turn moist blue litmus paper red.
2. Acids are electrolyte and in solution form, they can conduct electricity.
3. Reaction with metals:

Acids react with metals to form salt and Hydrogen gas.


4. Reaction with metal oxides:

Acids react with metal oxides to form salt and water.


5. Reaction with metal hydroxides:

Acids react with metal hydroxides to form salt and water. This is called the neutralization reaction.


6. Reaction with metal carbonates:

Acids react with metal carbonates to form salt, water and Carbon dioxide gas.

Table 2: Ionization: Strong Acids and Weak Acids

Strong Acids	Weak Acids
Fully ionized	Partially ionized
Man-made/ Synthetic	Naturally occurring

Ionization:

By fully ionization, it means that all the molecules of the acid are ionized, yielding freely moving H⁺ ions in their aqueous solutions. Weak acids do not have the tendency to completely ionize into their respective ions in their aqueous solutions. According to thumbs rule, only 4 out of 100 molecules will ionize to form H⁺ ions in weak acids.

Table 3: Acids and their basicity

Acid	Explanation	Example
Monobasic acid	1 mole of acid has 1 mole of H+ ions	HCl = 1 molecule of H2SO4 contains 1 H+ ion
Dibasic acid	1 mole of acid has 2 moles of H+ ions	H2SO4 = 1 molecule of H2SO4 contains 2 H+ ions
Tribasic acid	1 mole of acid has 3 moles of H+ ions	H3PO4 = 1 molecule of H3PO4 contains 3 H+ ions

Neutralization:

A neutralization reaction is defined as a reaction between an acid and a base in which the H⁺ ions of the acid, giving acid, its acidic nature reacts with the OH^- ions of the base to form water; a neutral liquid.

Ionic Equation:

Complete Equation:

Salt:

Salt is a by-product of neutralization reaction.