Chemistry Past Questions and Answers

In the preparation of carbon monoxide by heating ethanedioic acid with concentrated sulphuric acid, the concentrated sulphuric acid act as?

A An oxidizing agent
B A reducing agent
C A dehydrating agent
D A reaction medium
E A catalyst

Question 37:

When copper powder is heated with concentrated sulphuric acid, the gas produced is?

A Hydrogen sulphide
B Sulphur dioxide
C Sulphur trioxide
D Hydrogen pentasulphide
E Sulphur pentoxide

Question 38:

Magnesium ribbon was added to each of the following aqueous solution in turn: H₂SO₄, AgNO₃, HNO₃, HCl, NH₃, HCl, NH₃. In which case does the magnesium become covered with a dark precipitate?

A H₂SO₄
B AgNO₃
C HNO₃
D NH₃
E HCl

Question 39:

How many grams of methylacetylene (propyne) CH₃ – C Îž CH will completely discharge the colour of 8g of bromine?
(Br = 80, C = 12, H = 1)

A 0.5
B 1.0
C 2.0
D 3.0
E 4.0

Question 40:

What weight of sodium hydroxide is required to make 500 cm³ of 0.2 M solution?
(Na = 23, O = 16, H = 1)

A 40 g
B 20 g
C 10 g
D 4 g
E 2 g