Acids and Bases

• Curd, lemon juice, orange juice and vinegar taste sour as they contain acids and chemical nature of such substances is acidic.
• The word acid comes from the Latin word ‘acere’ which means sour.
• The acids in these substances are natural acids.
• Some substances are bitter in taste.

Baking soda

• If we rub baking soda solution between fingers, it feels soapy. Substances like these which are bitter in taste and feel soapy on touching are known as bases.
• Such substances are said to be basic.
• The substances which are neither acidic nor basic are called neutral substances.

For example water is neutral i.e. neither acidic nor basic.