Chemistry Past Questions and Answers

Copper sulphate solution was electrolysed using the apparatus show above. Which of the following changes are observed?

A The bulb lights and copper is deposited at both electrodes
B The bulb lights and copper is deposited at the anode and disappears from the cathode
C The bulb lights and copper is deposited at the cathode and oxygen liberated at the anode
D The bulb lights and copper is deposited at the cathode and disappears from the anode
E The bulb lights but no additional changes are observed

Question 42:

The following arrangement of elements in order of decreasing number of outer electrons; One of the elements is wrongly placed. Which is it? ALUMINIUM, CHLORINE, SILICON, MAGNESIUM AND SODIUM.

A Chlorine
B Aluminium
C Silicon
D Magnesium
E Sodium

Question 43:

Which of the following tests would confirm-unequivocally that a solution X contain the sulphate ion if it gives with

A Silver nitrates solution, a white precipates insoluble in dilute HNO₃
B Barium chloride solution, a white precipitate insoluble in dilute H₂SO₄
C Barium chloride solution, a white precipitate insoluble in dilute HCl
D Barium chloride solution a white precipitate soluble in dilute ammonia
E Barium chloride solution a white precipitate insoluble in dilute HCl

Question 44:

When copper (ii) sulphate solution is treated with excess ammonium hydroxide, a precipitate is first formed, and then this dissolves to give a deep blue solution. This deep blue solution is a

A Cu(OH)₂
B CuSo₄.5H₂O
C (NH₄)₂SO₄
D Cu(NH₃)₄(OH)₂
E CuSO₄.(NH₄)₂SO₄.2H₂O

Question 45:

Which of the following derivatives of nitrogen affords an aqueous solution having a pH of less that 7?

A N₂O
B NO
C NO₂
D NaNO₃
E NH₃