Chemistry Past Questions and Answers

2X_(aq) + MnO_2(s) + 4H⁺_(aq) â†’ X_2(g) + Mn²⁺_(aq) + 2H₂O.
The reaction above can be used for the laboratory preparation of all halogens except fluorine because it is?

A A poisionous gas
B An oxidizing agent
C Electronegative in nature
D Highly reactive

Question 32:

The removal of rust from iron by treatment with tetraoxosulphate (IV) acid is based on the?

A Hydrolysis of the iron
B Reaction of acid with base
C Oxidationof the rust
D Dehydration of the iron

Question 33:

Which of the additives could improve the quality of steel?

A Silicon
B Sulphur and phosphorus
C Carbon
D Chromium and nickel

Question 34:

Sodium hydroxide is prepared commercially from sodium chloride solution by?

A Electrolysis using mercury as cathode
B Hydrolysis in steam using a catalyst
C Electrolysis using iron as anode
D Treating sodium chloride with ammonia and carbon (IV) oxide

Question 35:

A sample of a substance containing only C and H burns in excess O₂ to yield 4.4g of CO₂
and 2.7 g of H₂O. The empirical formula of a substance is?
(C = 12, O = 16, H = 1)

A CH₃
B CH₂
C CH₄
D C₂H₂₄