Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : In expensive scientific instruments, silica gel is kept in watch-glasses or in semipermeable membrane bags.
Reason (R) : Silica gel adsorbs moisture from air via adsorption, thus protects the instrument from water corrosion (rusting) and / or prevents malfunctioning.
In the light of the above statements, choose the correct answer from the options given below :
Assertion (A) : In expensive scientific instruments, silica gel is kept in watch-glasses or in semipermeable membrane bags.
Reason (R) : Silica gel adsorbs moisture from air via adsorption, thus protects the instrument from water corrosion (rusting) and / or prevents malfunctioning.
In the light of the above statements, choose the correct answer from the options given below :
- (A)(A) is false but (R) is true
- (B)(A) is true but (R) is false
- (C)Both (A) and (R) are true and (R) is the correct explanation of (A)✓ Correct
- (D)Both (A) and (R) are true but (R) is not the correct explanation of (A)
Answer: (C)
Solution
Silica gel is a porous, strongly hygroscopic solid that holds water on its large internal surface by physical adsorption. Set in a watch-glass or a permeable bag beside a delicate instrument, it draws moisture from the surrounding air, keeping the metal parts dry and so preventing both rusting and the malfunctioning that damp would cause. This drying by adsorption is precisely why the gel is placed there, so the statement and its explanation are both true and the second correctly accounts for the first.
JEE Main · 2023 · 30 Jan 2023 · Shift 1 · Single correct option