2021 GS Paper I, all questions
UPSC Prelims 2021 · GS Paper I
Question 71: Science and Technology
Water can dissolve more substances than any other liquid because
ait is dipolar in nature
bit is a good conductor of heat
cit has high value of specific heat
dit is an oxide of hydrogen
AnswerUPSC’s answer is (a).
A water molecule is dipolar: oxygen carries a slight negative charge and the hydrogens a slight positive one. These poles attract and pull apart ions of salts and surround polar molecules such as sugars, which is why water dissolves more substances than any other common liquid. Heat conduction, specific heat and being an oxide of hydrogen do not explain solvent power. Remember: polarity makes water the universal solvent.
Why each option is right or wrong
- (a) Right: its polar nature lets water pull apart ionic and polar substances.
- (b) Wrong: heat conduction has no bearing on dissolving power.
- (c) Wrong: high specific heat concerns heat capacity, not solvent power.
- (d) Wrong: being an oxide of hydrogen describes its composition and does not explain its solvent power.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2021, General Studies Paper I, Series A. The paper on upsc.gov.in.