Non-metals and their compounds

11.pure water is
 
A. acidic
 
B. alkaline
 
C. Moody
 
D. none of these
 
Option”C” is correct
12.The pH value of pure water is
 
A. 2
 
B. 7
 
C. 9
 
D. 14
 
Option”B” is correct
13.At what temperature is the density of water the highest?
 
A. 0°C
 
B. 4°F
 
C. 4 K
 
D. 4°C
 
Option”D” is correct
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
 
Option”A” is correct
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
 
Option”B” is correct
16.The chemical formula of water is –
 
A. O₂
 
B. CO₂
 
C. H₂O
 
D. CH₄
 
Option”C” is correct
17.What percentage of the world’s land area is covered by water
 
A. 71%’
 
B. 76%’
 
C. 66%’
 
D. 29%’
 
Option”A” is correct
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
 
Option”C” is correct
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
 
Option”B” is correct
20.Potassium permanganate to water –
 
A. disinfects
 
B. makes it delicious
 
C. makes transparent
 
D. makes odor free
 
Option”A” is correct