UPSC Prelims 2003 Q144: Science & Technology – Chemistry
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?
- (a) Only 1
- (b) Only 2
- (c) Both 1 and 2
- (d) Neither 1 nor 2
Answer: (a) Only 1
Explanation
Ionic compounds
| Statement | Verdict |
|---|---|
| 1. Ionic compounds are insoluble in alcohol | True as a general statement (soluble in water, insoluble in organic solvents) |
| 2. Ionic compounds in the solid state are good conductors | False: they conduct only when molten or dissolved |
Only statement 1 is correct.
Answer: (a) Only 1.
Why each option is right or wrong
- (a) CORRECT. Only statement 1 is correct.
- (b) Incorrect. Solid ionic compounds do not conduct.
- (c) Incorrect. Statement 2 is false.
- (d) Incorrect. Statement 1 is accepted as correct.
Key point
Ionic solids: high melting point, brittle, conduct when molten or in solution.
Remember
Ionic compounds conduct only when molten or dissolved, not as solids.
Common mistakes
- Thinking solid ionic compounds conduct electricity.
- Believing they dissolve in all solvents.
- Mixing metals' conduction with salts.
Exam tip
Ions must be free to move to conduct.
Sources
- NCERT Class X Science — Metals and Non-metals
- NCERT Class XI Chemistry — Chemical Bonding and Molecular Structure (ionic bond)