Chemistry Past Questions and Answers

The iron (III) oxide impurity in bauxite can be removed by?

A Fractional crystallization in acid solution
B Dissolution in sodium hydroxide and filtration
C Extraction with concentrated ammonia and reprecipitation
D Electroysis of molten mixture

Question 462:

Which of the following does NOT contain aluminium as component?

A Over-head cables
B Duralumin
C Container for caustic soda
D Container for nitric acid

Question 463:

A white solid suspected to be lead trioxonitrate (V) zinc trioxocarbonate (IV) or calcium trioxocabonate (IV) was heated strongly. Its residue which was yellow when hot and white when cold is?

A Lead (II) oxide
B Calcium oxide
C Zinc oxide
D Lead nitrate

Question 464:

Which of the following compounds would give lilac flame coloration and a white precipitate with acidified barium chloride solution?

A KCI
B NaNO3
C K2SO4
D CaSO4

Question 465:

How will a metal X, which reacts explosively with air and with dilute acids be best extracted from its ores?

A Electrolysis of solution of its salts
B Decomposition of its oxides
C Displacement from solution by an alkali metal
D Electroiysis of fused salt