Oxidation and reduction - Jamb Chemistry Past Questions and Answers

Question 91:

• JAMB 2014

Zn _(s) + CuSO ₄(aq) → ZnSO ₄(aq) + Cu _(s)
In the reaction above, the oxidation number of the reducing agent changes from

A. 0 to + 4
B. 0 to + 2
C. + 1 to + 2
D. + 1 to + 3

Question 92:

• JAMB 2014

H ₂O _(g) + C _(s) → H_2(g) + CO_(g)
The oxidizing agent in the reaction above is

A. CO_(g)
B. C_(s)
C. H₂O_(g)
D. H_(2)(g)

Question 93:

• JAMB 2015

Cu₂S_(s) + O2(g) = 2CU_(s) + SO2_2(g)

A. +1 to 0
B. 0 to +2
C. +2 to +1
D. 0 to +1

Question 94:

• JAMB 2015

An oxidation state of Cr in K2CrO7

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

Question 95:

• JAMB 2015

The elements that belong to the third period of periodic table are

A. Li, Be, Al and D
B. Na, P, O and Cl
C. B, C, N, and O
D. Na, Mg, S and Ar