Which of the following can be obtained by fractional distillation?
Nitrogen from liquid air
Sodium chloride from sea water
Iodine from a solution of Iondine in carbon tetrachloride
Sulphur from a solution of sulphur incarbon disulphide
Correct answer is A
No explanation has been provided for this answer.
0.20
0.30
0.04
5.87
Correct answer is A
0.1F ↔ 2.95 g Ni = 0.4F ↔ 11.8 g Ni
No of moles = (11.8)/(58.2) = 0.20 moles
If 10.8 g of silver is deposited in a silver coulometer volume of oxygen liberated is?
0.56 dm3
5.60 dm3
11.20 dm3
22.40 dm3
Correct answer is A
Ag+ + e-
H = 108 g Ag
= 0.11 10.8 Ag
4OH → O2 + 2H2O + 4e
4F ↔ 1mole O2
4F = 22.4 dm3 χ 0.1 = 0.56 dm3
What volume of 11.0 M hydrochloric acid must be dilute to obtain 1 dm3 of 0.05 M acid?
0.05 dm3
0.10 dm3
0.55 dm3
11.0 dm3
Correct answer is A
No explanation has been provided for this answer.
What is the concentration of H+ ions in moles per dm3 of a sodium of pH 4.398?
4.0 χ 10-5
0.4 χ 10-5
4.0 χ 10-3
0.4 χ 10-3
Correct answer is A
PH = -log (H+)
(H+) = 10-4.348 = 4.0 χ 10-5