UPSC Prelims 2003 · General Studies

Question 108: Science and Technology

Assertion (A): Unsaturated fats are more reactive compared with the saturated fats. Reason (R): Unsaturated fats have only single bonds in their structure.

aBoth A and R are individually true and R is the correct explanation of A

bBoth A and R are individually true but R is NOT the correct explanation of A

cA is true but R is false

dA is false but R is true

AnswerThe answer is (c).

Unsaturated fats contain carbon-carbon double bonds, which can add hydrogen or other atoms, so they are more reactive than saturated fats, whose bonds are all single; A is true. R says unsaturated fats have only single bonds, which is false, and it contradicts the very reason A is true. Hydrogenation of vegetable oils to make vanaspati is the standard example.

A. Double bonds make unsaturated fats more reactive.
R. Unsaturated fats have double bonds, not only single bonds.

How you could have got this

If you were sure statement 1 is correct, (d) goes. Then judge the second statement; if it is correct too, decide whether it explains the first.

This follows an unofficial answer: UPSC has not published its key for this year, and if that answer is wrong, so is this path.

Which options go is worked out from UPSC’s key and the options, not by a model.

Why each option is right or wrong

(a) R is false, so it cannot explain A.
(b) R is false, so 'both true' fails.
(c) Correct: A is true and R is false.
(d) A is true, so 'A false' fails.

Explanation: written by UPSC Grade, not by UPSC.

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Source: UPSC, Civil Services (Preliminary) Examination 2003, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.