Full chem

Acids, Bases and Salts


 Acid: Turns blue litmus colour to red
 Base: Turns red litmus colour to blue
 Bases which are soluble in water are called alkalis. Example KOH, Mg(OH)2
 Turmeric is a natural indicator
 Reaction of acid with metals
 In most cases, metals replace hydrogen from acids.



 Metal oxide + Acid
 Metal oxide + Acid → Salt + Water
 Reaction of base with metals
 2NaOH + Zn →Na2ZnO2(sodium zincate) + H2

 Acids with metal carbonate and hydrogen carbonate
 Carbonate + Acid → Salt + Water + CO2

 Further on passing the carbon dioxide gas evolved through lime water.
 Ca(OH)2 + CO2 → CaCO3 + H2O

 Acid – Base reaction

Acid + Base → Salt + Water



 In water solution

Acid → H+ ion ; H+ + H2O → H3O+
Base → OH– ion




 Higher H+ concentration → Strong acid
 Lower H+ concentration →Weak acid
 Higher the OH– concentration → Stronger the base
 pH Measure
 pH → Measure of acidity →Measure H+ concentration on the scale (0 – 14)