UPSC Prelims 2000 · General Studies
Question 108: Science and Technology
Match List I with List II and select the correct answer using the codes given below the Lists: List I I. German Silver II. Solder III. Bleaching Powder IV. Hypo List II A) Tin B) Nickel C) Sodium D) Chlorine Codes:
AnswerThe answer is (d).
German silver is an alloy of copper, zinc and nickel, with no silver in it. Solder is an alloy of tin and lead. Bleaching powder, calcium oxychloride, is a source of chlorine. Hypo is sodium thiosulphate, used as a fixer in photography, and so goes with sodium. Learn each compound or alloy with its key element.
- I. German silver: nickel (B).
- II. Solder: tin (A).
- III. Bleaching powder: chlorine (D).
- IV. Hypo (sodium thiosulphate): sodium (C).
Why each option is right or wrong
- (a) Puts German silver with tin and solder with nickel, both wrong.
- (b) Puts bleaching powder with sodium and hypo with chlorine, both wrong.
- (c) Puts German silver with tin, solder with nickel, bleaching powder with sodium and hypo with chlorine, all wrong.
- (d) Right: German silver-nickel, solder-tin, bleaching powder-chlorine, hypo-sodium.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2000, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.