Q. 25.0( 1 Vote )
What is rancidity? Give some examples and some precaution also.
The term “rancidity” is often used in association with butter (oil). When we use old, left over cooking oil for making food stuff, it is found to have foul odour called rancidity.
i. Chemically, rancidity is an oxidation reaction.
ii. When oils or fats are left aside for a long time, they undergo air oxidation and become rancid.
iii. Example: Butter, ghee, or any food that has been made in such oils.
Precautions to prevent rancidity are as follows:
i. Keep food (snacks cooked in oil) in air tight containers, as this prevents the interaction of the oil and oxygen in the air and thus oxidation of fats doesn’t occur.
ii. Use of gases like nitrogen in packed foods prevents oxidation of food.
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i. What is observed when a solution of potassium iodide is added to a solution of lead nitrate taken in a test tube?
ii. What type of reaction is this?
iii. Write a balanced chemical equation to represent the above reaction.
A brown substance ‘X’ on heating in air forms a substance ‘Y’. When hydrogen gas is passed over heated ‘Y’, it again changes back into ‘X’.
i. Name the substance ‘X’ and ‘Y’
ii. Name the type of chemical reactions occurring during both the changes.
iii. Write the chemical equations of the reactions.Xam idea - Science