2009 General Studies, all questions
UPSC Prelims 2009 · General Studies
Question 65: Science and Technology
In a dry cell (battery), which of the following are used as electrolytes?
aAmmonium chloride and Zinc chloride
bSodium chloride and Calcium chloride
cMagnesium chloride and Zinc chloride
dAmmonium chloride and Calcium chloride
AnswerThe answer is (a).
A dry cell (Leclanche cell) has a zinc container as the anode and a graphite rod as the cathode, surrounded by manganese dioxide mixed with carbon. The electrolyte is a moist paste of ammonium chloride and zinc chloride. The manganese dioxide acts as a depolariser, taking up hydrogen so that the cell does not lose voltage.
Why each option is right or wrong
- (a) Right: ammonium chloride and zinc chloride.
- (b) Sodium chloride and calcium chloride are not used in dry cells.
- (c) Magnesium chloride is not the electrolyte.
- (d) Calcium chloride is not used; ammonium chloride is paired with zinc chloride.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2009, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.