Corrosion, Rusting and Rancidity

  • Corrosion and Rusting:

The process due to which metal are slowly eaten away by the reaction  of air water and chemical presents in the atmosphere is called corrosion.

The corrosion of iron is precisely known as Rusting.

That is,

 Fe + O2 + H2O –> Fe2. O3.nH2O

Prevention:

  • Rusting of iron can be prevented by covering its surface by Paints, grease, enamel, that does not allowed to air, moisture, Come in contact with it. And no rusting occur this is known as Barrier protection.
  • Rusting of iron can be prevented by galvanization Zinc metal does not corrode on exposure to air so zinc counting prevent iron from rusting. Zinc itself form protective coating of basic zinc carbonate.
  • Rusting can be prevented by counting the surface iron object with chromium tin, nickel, and aluminium.
  • Rusting can be prevented by converting it into alloy with chromium and nickel . This alloys is called  stainless steel.
  • Rancidity:

It is the process slow oxidation of oil and fat (which are volatile in nature) present in the food material resulting in the change of smell and test in them.

How to prevent rancidity?

  • Keeping food materials in air tights containers.
  • Refrigeration of cooked food at low temperature.
  • Packing of food item like potato wafers etc. In packed containing nitrogen gas instead of air.
  • Avoid keeping the cooked food and food materials  In direct sunlight.
  • By adding antioxidants g. BHA ( Butylated Hydroxy anisole)  and BHT (Butylated Hydroxytoluene).

Question Answer

(1) What is corrosion?

Answer: The process due to which  metal are slowly eaten away by the reaction  of air water and chemical presents in the atmosphere is called corrosion.

(2) Write the prevention from rusting and corrosion?

Answer: Prevention:

  • Rusting of iron can be prevented by covering its surface by Paints, grease, enamel, that does not allowed to air, moisture, Come in contact with it. And no rusting occur this is known as Barrier protection. .
  • Rusting of iron can be prevented by galvanization Zinc metal does not corrode on exposure to air so zinc counting prevent iron from rusting. Zinc itself form protective coating of basic zinc carbonate.
  • Rusting can be prevented by counting the surface iron object with chromium tin, nickel, and aluminium.
  • Rusting can be prevented by converting it into alloy with chromium and nickel . This alloys is called  stainless steel.

(3) What is rancidity?

Answer:   It is the process slow oxidation of oil and fat ( which are volatile in nature) present in the food material resulting in the change of smell and test in them.

(4) Write prevention of rancidity?

Answer:  Prevention:

  • Keeping food materials in air tights containers.
  • Refrigeration of cooked food at low temperature.
  • Packing of food item like potato wafers etc. In packed containing nitrogen gas instead of air.
  • Avoid keeping the cooked food and food materials  In direct sunlight.
  • By adding antioxidants  e.g. BHA (Butylated Hydroxy anisole)  and BHT ( Butylated Hydroxytoluene).

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