Question

Baeyer’s reagent is:
A) Aqueous bromine solution
B) Neutral permanganate solution
C) Acidified permanganate solution
D) Alkaline potassium permanganate solution

Answer 1

Hint: Baeyer’s reagent is widely used in the chemical industry as it acts as a strong oxidising agent. It is also on the World Health Organisation’s list of essential medicines as it also has wide medicinal uses.

Complete Step by Step Solution:
Baeyer’s reagent was discovered by a German chemist named Adolf von Baeyer. It is widely used in chemistry as a qualitative test that helps to identify the presence of unsaturation which can be in the form of double bonds or triple bonds.

Baeyer’s reagent is an alkaline solution of potassium permanganate that acts as a very strong oxidising agent when the reaction takes place with double or triple bonds. When the oxidising reaction takes place, it leads to the change of colour from purplish pink to brown.
Hence, option D is the correct answer

Additional Information:
Baeyer’s reagent has a wide variety of applications such as follows:
1) It is widely used for medicinal purposes for the treatment of diseases such as dermatitis, impetigo, pemphigus, and fungal infections of the foot.
2) It is also used as a water treatment which helps to get rid of the rotten- egg smell that occurs in the wells due to the presence of iron and hydrogen sulphide.
3) It is also used for the synthesis of various organic compounds such as ascorbic acid, chloramphenicol, saccharin, and pyrazinoic acid.
4) Due to its strong oxidising nature, Baeyer’s reagent also has various analytical uses such as in redox titrations, to determine the kappa number of the wood pulp, etc.
5) Baeyer’s reagent also helps in the preservation of fruits by removing ethylene thereby increasing the shelf life of fruits up to 4 weeks without refrigeration.
6) It is also used in fire services and survival kits.

Note: Earlier it was used by the photographers as a component of flash powder. It is not used these days and is replaced by other oxidising substances as permanganate solutions can be unstable. As it is a powerful oxidising agent it should be handled with care as after coming in contact with the skin, it can lead to a formation of a permanent brown stain.