Page 22 - Chemistry - XI

Q3. What is the eff ect of increase of external pressure on the boiling point?
Ans. The boiling point increases with the increase in external pressure.

Q4. What is the eff ect of decrease of external pressure on the boiling point?
Ans. The boiling point decreases with the decrease in external pressure.
Q5. What is the eff ect of impurities on boiling point of a liquid?
Ans. The boiling point of liquid increases on adding impurities because vapour pressure of solution
becomes less and it is to be heated at higher temperature so that its vapour pressure becomes equal
to the atmospheric pressure.

COMPETENCY BASED QUESTIONS

Multiple Choice Questions

Q1. Potash alum is a
(a) double salt (b) complex salt (c) basic salt (d) neutral salt

Q2. The crystals of benzoic acid are prepared by dissolving in
(a) water (b) benzene (c) alcohol (d) ether

Q3. What is the role of dil. H SO while dissolving CuSO ?
2 4 4
(a) Prevents hydrolysis (b) Prevents oxidation (c) Prevents reduction (d) All of these

Q4. What is the colour of anhydrous CuSO ?
4
(a) White (b) Blue (c) Green (d) Dirty white

Q5. Sugar and salt can be separated by
(a) crystallisation (b) fractional crystallisation

(c) distillation (d) fractional distillation
Q6. Isomorphous compounds have
(a) same crystal structure (b) diff erent crystal structures

(c) allotropes (d) same melting point
Q7. The purity of a solid salt can be checked by its

(a) melting point (b) boiling point (c) solubility (d) colour
Q8. The boiling point of water at a hill station would be

(a) 100°C (b) < 100°C (c) > 100°C (d) can’t be predicted
Q9. What is boiling point of sea water?

(a) 100°C (b) < 100°C (c) > 100°C (d) 98°C
Q10. What is melting point of ice mixed with common salt?

(a) 0°C (b) < 0°C (c) > 0°C (d) can’t be predicted

Answer key
Answer
Answer key key
1. (a), 2. (b), 3. (a), 4. (d), 5. (b), 6. (a), 7. (a), 8. (b), 9. (c), 10. (b)1. (a), 2. (b), 3. (a), 4. (d), 5. (b), 6. (a), 7. (a), 8. (b), 9. (c), 10. (b)
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