Oxidation and reduction - Jamb Chemistry Past Questions and Answers

Question 71:

• JAMB 2004

The oxidation state of chlorine in HClO₄ is

A. -5
B. -1
C. +1
D. +7

Question 72:

• JAMB 2004

Which of the following acts as both reducing and oxidized agent?

A. H₂
B. SO₂
C. H₂S
D. CO₂

Question 73:

• JAMB 2005

In which of the following reactions can the oxidation number of the nitrogen be said to have increased?

A. 2NO_(g) + O_2(g) → 2NO_2(g)
B. NO_(g) + Cl_2(g) → NOCl_2(l)
C. FeSO_4(aq) + NO_(g) → Fe(NO)SO_4(s)
D. NO_(g) + Br_2(l) → NOBr_2(l)

Question 74:

• JAMB 2005

A concentrated solution containing H⁺, Cu²⁺, OH^- and Cl^- was electrolyzed using platinum electrodes.
The ion that will be discharged at the cathode is

A. Cu²⁺
B. Cl^-
C. H⁺
D. OH^-

Question 75:

• JAMB 2005

Natural water collected from rivers and ponds contain oxygen, carbon (IV) oxide and

A. Nitrogen
B. Hydrogen
C. Chlorine
D. Sulphur
E. Oxide