Acids, bases and salts · अम्ल, क्षारक और लवण
A free Chemistry lesson for Class 7 children.
Acids taste sour. Lemon juice, vinegar and curd contain acids.
Bases taste bitter and feel soapy. Soap and baking soda are bases.
Never taste or touch chemicals in the laboratory.
An indicator changes colour to show whether something is an acid or a base.
Acids turn blue litmus red. Bases turn red litmus blue.
Turmeric turns red in a base. China rose turns acids pink and bases green.
An acid and a base cancel each other. This is neutralisation. It gives salt and water.
On the pH scale, below 7 is acidic, 7 is neutral and above 7 is basic.