Question

Tanning of leather is the:
(A) Colouring of leather by chemicals
(B) Drying process to make the leather hard
(C) Polishing of leather to make it look attractive
(D) Coagulative hardening of the leather by chemicals

Answer 1

Hint: Tanning is the process through which the extra fat of the skin or hide is removed to make it fit for the purpose . The fat present in the dead skin will interfere during the manufacturing and hence it has to be dealt with effectively. The process of tanning does that.

Complete answer: When the skin is extracted it is full of moisture , if not chemically preserved or processes it is going to rot and will become unfit. Therefore, some manipulation of the leather has to be done to make it fit and usable. Tanning involves chemical manipulation of the skin . Animal skin (hide) is colloidal in nature and has positively charged particles, whereas tanning consists of negatively charged colloidal particles. When the skin or we can say hide is soaked /sunk in tanning solution , mutual coagulation takes place and as a result of it , the leather gets hardened . In some cases , colouring is also done simultaneously with coagulation . The most prominent definition of tanning is coagulative hardening of the leather by chemicals.

Hence , the correct option is (D).

Note: Animal skin or fat has a lot which is not favourable hence this process is done. A material has to go through a lot of processes before it can be finally utilized.