Chemistry Past Questions and Answers

Given the mean atomic mass of chlorine prepared in the laboratory to be 35.5 and assuming that chlorine contains two isotopes of mass number 35 nad 37, what is the percentage composition of the isotope of mass number 35?

A 20
B 25
C 50
D 75
E 90

Question 22:

When dilute hydrochloric acid is added to iron(ll)sulphide, the gas evolved will?

A Turn moist red litmus paper blue
B Turn lime water milky
C Blacken lead acurate paper
D Rekindle a glowing splint
E Burn a sqeakly pop

Question 23:

In which of the following is the oxidation state of oxygen different from its value in water?

A OH^-
B H₃O⁺
C O^-
D H₂O₂
E SO₂

Question 24:

Which of the following silver halides is readily soluble in ammonium hydroxide?

A Agl
B AgBr
C AgCl
D AgF
E None of the above

Question 25:

The chemical reaction which takes place at the anode (positive electrode) in electrolysis is?

A Oxidation
B Hydrolysis
C Dissociation
D Reduction
E Disproportionation