Write the short note on: Rancidity

Rancidity is the complete or incomplete oxidation or hydrolysis of fats and oils when exposed to air, light, or moisture or by bacterial action, resulting in unpleasant taste and odour of food. It’s a term used to describe the oxygen damage in food. An example of rancidity is when a chips pack is exposed to atmospheric air which results in a change in taste and odour.

What do you understand by Double-displacement reaction?

Double displacement reactions, two compounds react by an exchange of ions to form two new compounds are called double displacement reactions. Positive ions (cation) and the negative ions (anion) of the two reactants switch places, forming two new compounds or products. For example, When barium chloride combines with sodium sulphate in the form of their aqueous solutions, a white precipitate of barium sulphate is formed which is insoluble in water. Na 2 SO 4 aq + BaCl 2 → BaSO 4 s + 2 NaCl aq