1998 General Studies, all questions

UPSC Prelims 1998 · General Studies

Question 129: Science and Technology

Assertion (A): Phenyl is used as a household germicide. Reason (R): Phenyl is a phenol derivative and phenol is an effective germicide.

aBoth A and R are true, and R is the correct explanation of A
bBoth A and R are true, but R is NOT a correct explanation of A
cA is true, but R is false
dA is false, but R is true

AnswerThe answer is (a).

Phenyl, the household floor and drain cleaner, is made from phenolic compounds such as cresols emulsified in water. Phenol and its derivatives kill germs by denaturing their proteins; carbolic acid (phenol) was the first antiseptic, used by Lister. Both statements are true, and R explains A: phenyl works as a germicide because it is a phenol derivative.

  • A. Phenyl is used as a household germicide.
  • R. Phenyl is a phenol derivative and phenol is an effective germicide.

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) Right: phenyl is a germicide because it is a phenol derivative.
  • (b) R is the reason for A, not just a true remark.
  • (c) R is true, so this fails.
  • (d) A is true, so this fails.

Explanation: written by UPSC Grade, not by UPSC.

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Source: UPSC, Civil Services (Preliminary) Examination 1998, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.