Chemistry Past Questions and Answers

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 202:

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 203:

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 204:

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

Question 205:

Detergents are more advantageous than soaps in hard water districts because

A On treatment with hard water they either form soluble calcium salts or do not react with calcium ion
B On treatment with hard water they form soluble calcium salts
C On treatment with hard water they form sodium salts
D On treatment with hard water they are converted into soaps
E On treatment with hard water they form more lather than soaps does