| 11. | pure water is |
A. acidic | |
B. alkaline | |
C. Moody | |
D. none of these |
| 12. | The pH value of pure water is |
A. 2 | |
B. 7 | |
C. 9 | |
D. 14 |
| 13. | At what temperature is the density of water the highest? |
A. 0°C | |
B. 4°F | |
C. 4 K | |
D. 4°C |
| 14. | The density of water on heating from 0 °C to 100 °C – |
A. Increases up to 4°C, then decreases | |
B. Decreases up to 4°C, then increases | |
C. increases with increasing temperature | |
D. decreases with increase in temperature |
| 15. | The higher boiling point of water than hydrogen sulphide or hydrogen chloride is due to |
A. polar covalent bond | |
B. hydrogen bonding | |
C. Vanderwaal Attractions | |
D. bipolar insulation |
| 16. | The chemical formula of water is – |
A. O₂ | |
B. CO₂ | |
C. H₂O | |
D. CH₄ |
| 17. | What percentage of the world’s land area is covered by water |
A. 71%’ | |
B. 76%’ | |
C. 66%’ | |
D. 29%’ |
| 18. | Water boiling point and freezing point when water is mixed with water |
A. will increase | |
B. will decrease | |
C. will gradually increase and decrease | |
D. will gradually decrease and increase |
| 19. | Disinfection of water is carried out in rural areas |
A. by sodium chloride | |
B. by chlorine | |
C. by potassium permanganate | |
D. by sodium sulfate |
| 20. | Potassium permanganate to water – |
A. disinfects | |
B. makes it delicious | |
C. makes transparent | |
D. makes odor free |