NECO Chemistry · Solutions, energy and chemical change
Redox reactions: NECO Chemistry Past Questions and Answers
What the WAEC syllabus covers in Redox reactions
Our summary: Oxidation and reduction, balancing redox equations, electrochemical cells, electrolysis and corrosion.
- Oxidation and reduction process ((1) Oxidation and reduction in terms of: (a) addition and removal of oxygen and hydrogen; (b) loss and gain of electrons; (c) change in oxidation numbers/states. (2) Determination of oxidation numbers/states.)
- Oxidizing and reducing agents ((1) Description of oxidizing and reducing agents in terms of: (a) addition and removal of oxygen and hydrogen; (b) loss and gain of electrons; (c) change in oxidation numbers/state.)
- Redox equations (Balancing redox equations by: (a) ion, electron or change in oxidation number/states; (b) half reactions and overall reaction.)
- Electrochemical cells (Definition/explanation.)
- Electrochemical cells: standard electrode potential ((1) Standard hydrogen electrode: meaning of standard electrode potential (E°) and its measurement. (2) Only metal/metal ion systems should be used.)
- Electrochemical cells: drawing of cell diagram and writing cell notation
- Electrochemical cells: e.m.f. of cells ((1) Electrochemical cells as a combination of two half-cells. (2) The meaning of magnitude and sign of the e.m.f.)
- Electrochemical cells: application of electrochemical cells ((1) Distinction between primary and secondary cells. (2) Daniell cell, lead acid battery cell, dry cells, fuel cells and their use as generators of electrical energy from chemical reactions.)
- Electrolysis (Definition.)
- Electrolysis: electrolytic cells (Comparison of electrolytic and electrochemical cells; weak and strong electrolyte.)
- Electrolysis: principles of electrolysis (Mechanism of electrolysis.)
- Electrolysis: factors influencing discharge of species (Limit electrolytes to molten PbBr₂ and NaCl, dilute NaCl solution, concentrated NaCl solution, CuSO₄(aq), dilute H₂SO₄, NaOH(aq) and CaCl₂(aq) (using platinum or graphite and copper electrodes).)
- Electrolysis: Faraday's laws (Simple calculations based on the relation 1 F = 96,500 C and mole ratios to determine mass, volume of gases, number of entities, charges etc. using half and overall reactions.)
- Electrolysis: practical application (Electroplating, extraction and purification of metals.)
- Corrosion of metals ((1) Corrosion treated as a redox process. (2) Rusting of iron and its economic costs. (3) Prevention based on relative magnitude of electrode potentials and preventive methods like galvanizing, sacrificial/cathodic protection and non-redox methods (painting, greasing/oiling etc.).)
Syllabus content © The West African Examinations Council (WASSCE (harmonised West African syllabus)). NECO questions are matched to the WAEC syllabus topic.
NECO Chemistry questions on Redox reactions
- NECO 2009In the electrolysis of dilute tetraoxosulphate (VI) acid using platinum electrodes, the products obtained at the anode are cathode respectively are
- NECO 2009What mass of copper in gram would be deposited by a current of 1.00ampere passing for 965 seconds through copper(II) tertraoxosulphate (VI) solution? [Cu 63.5…
- NECO 2009Sulphur has an oxidation number of +4 in
- NECO 2009The following equations represent redox reactions EXCEPT
- NECO 2008The electrode potential in volts of 2H ^+ (aq) / H 2 (q) system is
- NECO 2008During the electrolysis of sodium Chloride solution, hydrogen is discharged at the carbon cathode because
- NECO 2008If two metallic ions of the same concentration migrate to a graphite cathode, the one that would be preferentially discharged is that with the
- NECO 2003What mass of silver is deposited when a current of 2.6 A is passed through a solution of a silver salt for 40 minutes? [Ag= 108 ; F=96500C]
- NECO 2003Which method is used for the purification of copper from its ore?
- NECO 2003What is the change in the oxidation number of phosphorus in the following reaction? 4P(s) + 5O2(ag) → 2P2O5(s)
- NECO 2003In the reaction 2H2S(g) + SO2(g) → 2H2SO(I)+3S(s)SO2is acting as agent
- NECO 2003What change will occur during the electrolysis of brine using carbon electrodes?
- NECO 2003Chlorine displaces bromine from aqueous potassium bromide because
- NECO 2001Which statement BEST describes the process of oxidation?
- NECO 2001The green colour solution of an Fe2 salt changes to a brown solution of an Fe3+ salt by
- NECO 2001Faraday s first law of electrolysis can be expressed mathematically as
- NECO 2001Which compound can be used as a reducing agent in a reaction?
- NECO 2001The oxidation number of X in XO 4 ^ 3- is
Years with Redox reactions questions in DeeepSolve's question bank
From the past questions DeeepSolve holds, not a count of everything the exam body has set.
- 2009
- 2008
- 2003
- 2001