Waec Chemistry 2011 Past Questions and Answers

Question 36:

• WAEC 2011

Which of the following metals could be used as sacrifical anode for preventing the corrosion of iron?

A. Copper
B. Lead
C. Magnesium
D. Silver

Question 37:

• WAEC 2011

Consider the following electrochemical cell notation: M_(s) / M²⁺_(aq)// H⁺_(aq)/ H_2(g). The value of the electrode potential is positive when

A. Electrons flow from the metal electrode, M_(s) to hydrogen electrode, H_2(g)
B. Electrons fow from hydrogen electrode, H_2(g) to metal electrode, M_(s)
C. The flow of current is high
D. There is equilibrium between the flow of electrons from the hydrogen electrode, H_2(g) to metal electrode, M_(s)

Question 38:

• WAEC 2011

Which of the following compounds determines the octane rating of petrol?

A. 1,2,3 - trimethlpentane
B. 2,3,5 - trimethyloctane
C. 2,3,5 - trimethylpentane
D. 2,2,4 - trimethylpentane

Question 39:

• WAEC 2011

Which of the following compounds would react with ethanoic acid to give a sweet smelling liquid?

A. Alkane
B. Alkanol
C. Alkanal
D. Alkyne

Question 40:

• WAEC 2011

Which of the following separation techniques would show that black ink is a mixture of chemical compounds?

A. Crystallization
B. Chromatography
C. Filtration
D. Sublimation