Common Properties of all Acids and all Bases

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What do all Acids have in common?

• Acids react with metals to give salt and hydrogen gas. This can be generalized as

Acid + Metal → Salt + Hydrogen Gas

For example, hydrogen gas and zinc chloride are formed when hydrochloric acid reacts with Zinc metal. The reaction is

𝒁𝒏 + 𝟐𝑯𝑪𝒍 → 𝒁𝒏𝑪𝒍𝟐 + 𝑯𝟐

• All acids contain

For example, hydrochloric acid (HCl), sulphuric acid (𝐻2𝑆𝑂4), nitric acid (𝐻𝑁𝑂3) etc.

• When an acid is dissolved in water, it dissociates the

For example, Hydrochloric acid (HCl) gives hydrogen ion (𝐻⁺) and chloride ion (𝐶𝑙⁻) when it is dissolved in water. The reaction is

𝑯𝑪𝒍(𝒂𝒒) → 𝑯⁺ + 𝑪𝒍⁻

Are all compounds, which contain hydrogen, acidic in nature?

Let us understand this with the help of an experiment.

Things needed:

• A beaker
• A rubber cork
• Two iron nails
• A circuit with a battery, a bulb, and a switch

• Dilute hydrochloric acid
• Sulphuric acid
• Glucose solution or methyl alcohol

Procedure:

1. Take a
2. Keep a rubber cork with two iron nails fixed on it in the
3. Connect the nails to the two terminals of a battery. The bulb doesn’t
4. Add dilute hydrochloric acid to this beaker. Blub starts
5. Replace the solution of hydrochloric acid with sulphuric acid in place, the bulb still
6. Empty the beaker and clean
7. Add glucose (𝐶6𝐻12𝑂6) solution or methyl alcohol (𝐶𝐻3𝑂𝐻) to the The bulb

doesn’t glow.

The acid solution in water conducts electricity

Observation:

• When the nails are connected to the two terminals of a battery, the bulb doesn’t glow

because the loop is not completed as the rubber is a poor conductor of electricity.

• When dilute hydrochloric acid or sulphuric acid is added to the beaker, the bulb starts glowing. This means that current starts flowing in the
• When glucose solution or methyl alcohol is added to the beaker, the bulb doesn’t glow

because they do not dissociate the hydrogen ion in their aqueous solution.

Conclusion:

• Not all compounds containing hydrogen are

What do all Bases have in common?

• A base dissociates hydroxide in water which is responsible for the basic behaviour of a compound.

For example, when sodium hydroxide is dissolved in water, it dissociates hydroxide ion and sodium ion. The reaction is

𝑵𝒂𝑶𝑯(𝒂𝒒) → 𝑵𝒂⁺ + 𝑶𝑯⁻

• The anions (𝑂𝐻⁻𝑖𝑜𝑛𝑠) carry electric current in the
• A base shows its basic character because of the dissociation of the hydroxide

Dissociation of 𝑶𝑯⁻ions