Chemistry Past Questions and Answers

How many Faradays of electricity are required to liberate 9g of aluminium? [Al = 27]

A 0.1
B 0.3
C 1
D 2.7
E 3

Question 52:

At s.t.p, a mole of chlorine occupies 22.4dm³. If the temperature is changed to 35°C and the pressure to 750mHg the of the new volume will be [Cl = 35.5]

A \( ^{\text{760 x 22.4 x 308}} \text{750 x 273x 35.5} dm^3 \)
B \( ^{\text{760 x 22.4 x 308}} \text{750 x 273}^x dm^3 \)
C \( ^{\text{750 x 22.4 x 35.5}} \text{760 x 273dm3} \)
D \( ^{\text{760 x 22.4 x 35.5}} \text{750x22.3x273} \)
E \( ^{\text{760 x 22.4 x 35.5}} \text{750 x 308dm3} \)

Question 53:

What is the concentration (in mol dm³) of a solution containing 28 g of potassium hydroxide per 100 cm³ of solution? (K=39; H=1; 0=16)

A 0.01
B 0.05
C 0.1
D 0.5
E 2.8

Question 54:

Which method is used for the purification of copper from its ore?

A Distillation
B Electrochemical
C Electrolysis
D Neutralization
E Reduction

Question 55:

Ethene decolourises acidified potassium tetraoxomanganate(VII) solution. Which gas will decolourise bromine water?

A CH₄
B C₂H₆
C C₃H₆
D C₃H₈
E C₆H₆