UPSC Prelims 2003 · General Studies

Question 144: Science and Technology

With reference to ionic compounds, consider the following statements:

1.Ionic compounds are insoluble in alcohol.
2.Ionic compounds in the solid state are good conductors of electricity.

Which of these statements is/are correct?

aOnly 1

bOnly 2

cBoth 1 and 2

dNeither 1 nor 2

AnswerThe answer is (a).

Ionic compounds dissolve in polar solvents such as water but are generally insoluble in less polar organic solvents such as alcohol, so statement 1 is accepted. In the solid state the ions are fixed in the lattice and cannot move, so ionic solids do not conduct electricity; they conduct when molten or dissolved. So statement 2 is wrong.

1. Ionic compounds are generally insoluble in alcohol and other organic solvents.
2. In the solid state the ions cannot move, so ionic solids do not conduct.

Why each option is right or wrong

(a) Correct: only statement 1.
(b) Statement 2 is false.
(c) Statement 2 is false, so both cannot hold.
(d) Statement 1 is accepted as true, so 'neither' fails.

Explanation: written by UPSC Grade, not by UPSC.

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Source: UPSC, Civil Services (Preliminary) Examination 2003, General Studies. UPSC's own paper isn't online; the words are from a published compilation. The paper on upsc.gov.in.