Chemistry Past Questions and Answers

5cm³ of a saturated solution of sodium chloride at 30°C gave, on careful evaporation, 1.95g of solid salt. The solubility of sodium chloride at 30°C?
(Na = 23, Cl = 35.5)

A 5.00 mole dm³
B 5.67 mole dm³
C 6.00 mole dm³
D 6.67 mole dm³
E 7.00 mole dm³

Question 37:

In the extraction of iron, which of the following reactions does NOT take place in the blast furnace?

A CO₂ + C â†’ 2CO
B 2Fe₂O₃ + 3C → 4Fe + 3CO₂
C Fe₂O₃ + 3C â†’ 2Fe + 3CO₂
D CaCO₃ â†’ CaO + CO₂
E CaO + SiO₂ â†’ CaSiO₃

Question 38:

Pure sulphuric acid is a liquid of 1:84 density. What volume of it would be required to prepare 250 cm³ of 2.0 M solution?
(H = 1, S = 32, O = 16)

A 2.00
B 2.66
C 3.00
D 3.66
E 4.00

Question 39:

What mass of sodium carbonate solution is in 500 cm³ of 0.1 molar sodium carbonate solution?
(Na = 23, C = 12, O = 16)

A 10.6 g
B 5.3 g
C 500 g
D 10 g
E 20 g

Question 40:

Which of the following compounds and elements would sublime on exposure to the atmosphere?

A Ice
B Sulphur
C Phosphurous
D Iodine
E Potassium iodie