Question

Explain the following terms with one example each.
a. Corrosion
b. Rancidity

Answer 1

Hint: Both these terms refer to some kind of spoilage or destruction of the respective material such that it cannot be used for its intended function.

Complete step by step solution:
- Corrosion:
Corrosion refers to the natural destruction of metals in a way that compromises their ability to be strong and provide support to other structures. A metal is said to be corroded when the refined metal is converted into a more chemically stable form like an oxide, hydroxide, sulphate, or a sulphide. Corrosion involves chemical or electrochemical reactions with the molecules present in the fluid (gas or liquid) that surrounds it, and slows its ability to carry out the function it is supposed to. Corrosion may also be caused due to microbiological entities that are present.
The most common example of corrosion is the rusting of iron or steel. Most of the corrosion occurs due to the oxidation of iron into iron oxide. A reddish powdery residue is seen on the surfaces at the sites where rusting occurs.

- Rancidity:
Rancidity refers solely to the oxidation of fats and oils that are usually present in food. The oxidation may be either complete or partial. Rancidification of foodstuffs causes an extremely unpleasant taste and odour. The oxidation of unsaturated fatty acids into aldehydes and ketones can cause rancidity, this is known as oxidative rancidity. Other types of rancidity are microbial rancidity, where fats are broken down using enzymes, and hydrolytic rancidity, where triglycerides are hydrolysed to cause a foul odour.
All these types lead to the food being inedible and will cause harm to our bodies. An example of rancidity is spoiling of meat. Even if meat is immediately refrigerated, some of the poly-unsaturated fats will continue to degrade and become rancid. So, it is always better to consume meat as soon as it is bought.

Note: Please do not get confused between rancidity and corrosion, even though they both refer to spoiling and destruction of materials and substances, corrosion always refers to metals being destroyed due to oxidation and rancidity refers to fats being oxidized.