Jamb Chemistry 2009 Past Questions and Answers

Question 21:

• JAMB 2009

The colour changes observed when testing for reducing agents using acidified potassium heptaoxodichromate (IV) solution is

A. Yellow to purple
B. Orange to green
C. Green to orange
D. Purple to yellow

Question 22:

• JAMB 2009

The oxidation state of Cr in K₂Cr₂O₇ is

A. +7
B. +6
C. +5
D. 4

Question 23:

• JAMB 2009

Which of the following metals is purified commercially by electrolysis?

A. Zn
B. Fe
C. Sn
D. Cu

Question 24:

• JAMB 2009

What current will deposit 3.25g of zinc in 2hrs?
[Zn = 65, F = 96500 mol^-]

A. 3.25A
B. 2.00A
C. 1.34A
D. 0.67A

Question 25:

• JAMB 2009

C_(s) + H₂O_(g) → H_2(g) + CO_2(g)
ΔG for the reaction above at 1300k is -43KJ. At this temperature, the reaction is

A. Not feasible
B. At equilibrium
C. Feasible
D. Exothermic