Question

Which of the following techniques can be used to separate grains from husk?

• A. Winnowing
• B. Hand-picking
• C. Sieving
• D. Sublimation

Answer 1

The correct option is A

Winnowing

Explanation of correct option:

(A) Winnowing:

• Grain is separated from husk or chaff by the process of winnowing.
• In this process, the grains are allowed to fall from a height. The chaff being lighter is blown away by the wind and the grains form a separate heap.

Explanation of incorrect options:

(B) Hand-picking:

• It is a method of separating solid impurities from a solid-solid mixture.
• In this process, the visible solid impurities are picked up by hand.
• This method can be done only if the components can be distinguished by size, shape, or color.
• Example: separating stones from rice.

(C) Sieving:

• This is also a method of separating solid-solid mixtures when coarser particles are mixed with finer particles.
• On passing through a sieve, the finer particles pass through, while the coarser particles are left behind.
• Example: Separating the stone from sand at the construction site.

(D) Sublimation:

• The process of conversion of a solid directly into vapor without passing through a liquid state on heating is called sublimation.
• Example: A mixture of common salt and ammonium chloride can be separated by this method as ammonium chloride undergoes sublimation.

Hence, option (A) i.e. winnowing is correct.