UPSC Prelims 1998 · General Studies

Question 103: Science and Technology

Match List I with List II and select the correct answer using the codes given below the lists: List I I. Potassium bromide II. Potassium nitrate III. Potassium sulphate IV. Mono-potassium tartrate List II A. Fertiliser B. Photography C. Bakery D. Gunpowder Codes:

aI-B, II-D, III-A, IV-C

bI-B, II-D, III-C, IV-A

cI-D, II-B, III-C, IV-A

dI-D, II-B, III-A, IV-C

AnswerThe answer is (a).

Potassium bromide is used in photography, where it helps make the light-sensitive silver bromide of films and plates. Potassium nitrate (saltpetre) is an ingredient of gunpowder. Potassium sulphate supplies potassium and sulphur as a fertiliser. Mono-potassium tartrate, or cream of tartar, is used in baking powder. So I-B, II-D, III-A, IV-C.

I. Potassium bromide is used in photography (B).
II. Potassium nitrate is used in gunpowder (D).
III. Potassium sulphate is a fertiliser (A).
IV. Mono-potassium tartrate is used in baking (C).

Why each option is right or wrong

(a) Right: KBr-photography, KNO3-gunpowder, K2SO4-fertiliser, cream of tartar-bakery.
(b) Potassium sulphate is a fertiliser, not a bakery ingredient.
(c) Potassium bromide is photographic, not gunpowder, and potassium sulphate is not a baking ingredient.
(d) Potassium bromide and potassium nitrate are swapped, as are potassium sulphate and cream of tartar.

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.