Question

Which of the following chemicals can be used to detect starch, a common adulterant in milk ?
A. Sodium chloride
B. Iodine
C. Hydrochloric acid
D. Sodium hydroxide

Answer 1

Hint: The substances which can attach to starch structure can be used for or detection of its presence help us eliminate the adulterant. Any substance which reacts with starch may provide us with a test which can detect its presence.

Complete answer:
Adulteration in milk decreases the quality of milk and makes it dangerous. Substances like soap, starch, sugar and chemicals like formalin may be added to milk. Most of these adulterants are poisonous and cause health issues.
Amylose is present in a starch factor that produces a deep blue color in the presence of iodine. The iodine may slip in the coil of the amylose.
The iodine–starch test is an interaction that is used to detect the presence of starch or iodine. The chemical reaction of starch and iodine gives an intensely blue-black colour.
The triiodide ion in no time imparts an intense blue-black colour merely upon contact with starch. The intensity of the colour may be reduced with increase in temperature or because of the presence of water soluble organic solvents ( like ethanol). The test can't be illustrated at very low pH due to the fact that starch undergoes hydrolysis under these conditions. It is assumed that iodine–iodide combines with the starch and forms a polyiodide homopolymer.
The colour of the complex is so deep and intense that it can be detected even visually.

So, the correct answer is “Option B”.

Note:
Adultery can be lethal to human beings. We should always check on our food products.Iodine test provides us the opportunities of making the food we consume better. We may use tincture of iodine as an antiseptic, it contains such properties.