Chemistry Past Questions and Answers

In an attempt to remove sugar from a breaker containing a quantity of sand and sugar, 2 M ammonium chloride solution was accidentally added instead of water. Which of the following method could be used to remove the ammonium chloride from the mixture?

A Fractional distillation
B Crystallization
C Filtration followed by evaporation
D Evaporation followed by sublimation
E Filtration followed by sublimation

Question 162:

The alloy duralumin is used for the building of aeroplanes because it?

A Asborbs heat readily from sure thereby preventing the inside of the plane from getting cold at high attitudes
B Reflects sunlight readily, thereby keeping the inside of the plane cool
C Is extremely durable and possesses reflective ability
D Is easily the lightest building material
E Possesses both strenght and lightness

Question 163:

A solution X on mixing with AgNO3 solution, gives a white precipitate solution in NH3. A Solution Y, when added to X, also gives a white precipiate which is soluble on boiling. Solution Y contains?

A Ag+ion
B Pb2+ion
C Pb4+ion
D Zn2+ion
E Al3+ion

Question 164:

10cm3 of CO is mixed and sparked with 100cm3 of air containing 21% O2. If all the volumes measured at S.T.P. the volume of resulting gases would be?

A 90cm3
B 100cm3
C 105cm3
D 110cm3
E 115cm3

Question 165:

A sample of an oxide of mercury weighed 1.00g. When this was heated, oxygen was given off, and 1.00g of mercury metal only was left. What is the formula of the oxide?

A Hg2O
B HgO2
C HgO2
D HgO
E None of the above