Chemistry Past Questions and Answers

Which of the following bonds exist in crystalline ammonium chloride (NH4Cl)?

A Ionic and covalent
B Ionic and co-ordinate
C Ionic covalent and co-ordinate
D Covalent , co-ordinate and metalllic
E Ionic, covalent and metallic

Question 287:

When a pressure cooker is half filled with water, and heated to boiling point, then the pressure inside the cooker will?

A Decrease, since only a fraction of the water molecules has changed to vapour
B Remain constant, because the total number of water molecules has not changed
C Increase, because the water molecules can now reach every part of the sealed tube
D Decrease, since water boils under reduced pressure
E Increase, because the water vapour molecules now strike the walls of the tube more frequently because of their increased velocity

Question 288:

An element X has two isotopes, 2010X and 2010X, present in the ratio 1:3. The relative atomic mass of X would be?

A 20.5
B 21.0
C 21.5
D 22.0
E 22.5

Question 289:

Which of the following is a neutralization reaction? Addition of

A Nitric acid to hydrochloric acid
B Nitric acid to sulphuric acid
C Nitric acid to distilled water
D Nitric acid to sodium hydroxide
E Sodium chloride to distilled water

Question 290:

A current of 10.0A was passed for 1 hour through a solution of copper (ll) sulphate between the copper electrodes. Which of the following observation would be correct? (1 Faraday = 96,500 coulobms) (i) 0.186 mole of copper is dissolved from the anode. (ii) 0.372 mole of copper is deposited on the cathode. (iii) the original Cu2+ ion concentration of the solution remains unchanged. (iv) the original Cu2+ ion concentration of the solution decreases.

A I and ii
B I and iii
C I and iv
D Ii and iii
E Ii and iv