A chemical reaction in which both oxidation and reduction occur simultaneously is called a: a) Feral reaction b) Redox reaction c) Demug reaction d) Kerol reaction Answer: b
Nitrogen exhibits oxidation states in the range: a) –3 to +5 b) –3 to +3 c) –3 to +4 d) –3 to +6 Answer: a
The gain of electrons during a reaction is known as: a) Oxidation b) Reduction c) Radiation d) Both oxidation and reduction Answer: b
What causes the rusting of iron? a) Oxidation and reduction b) Reduction and oxygen reaction c) Reaction with CO₂ and oxygen d) Oxidation and chemical reaction with oxygen Answer: d
The loss of electrons in a reaction is called: a) Oxidation b) Reduction c) Radiation d) Oxidation and reduction Answer: a
What is formed when hydrogen burns in air? a) Ammonia b) Water c) Methane d) Carbonic acid Answer: b
The brown coating that forms on iron exposed to air is called: a) Dust b) Shovel c) Spade d) Rust Answer: d
The conversion of Fe²⁺ to Fe³⁺ is an example of: a) Oxidation b) Reduction c) Ionisation d) Nuclear reaction Answer: a
Which is NOT a feature of an oxidation reaction? a) Addition of hydrogen b) Addition of oxygen c) Loss of electrons d) Addition of an electronegative element Answer: a
Rusting of iron is caused by: a) Oxidation b) Carbonation c) Epoxidation d) Corrosion Answer: a
Rusting of iron is a: a) Physical change b) Electric change c) Photochemical change d) None of the above Answer: d
Coating a thin layer of zinc on steel or iron is known as: a) Hot dipping b) Tinning c) Galvanising d) Electroplating Answer: c
Which metal does NOT corrode easily due to its oxide layer? a) Copper b) Iron c) Aluminium d) Zinc Answer: c
Applying a protective layer of zinc on water pipes to prevent rusting is called: a) Zinc coating b) Alloy formation c) Vulcanization d) Galvanization Answer: d
Which method is NOT suitable to prevent rusting of iron? a) Annealing b) Greasing c) Galvanization d) Painting Answer: a
The metal primarily used for galvanising iron is: a) Zinc b) Mercury c) Cadmium d) Tin Answer: a
Potassium permanganate is used in water purification because it is a: a) Reducing agent b) Oxidising agent c) Sterilising agent d) Dissolving agent Answer: b
Rusting is a: a) Electrolysis process b) Oxidation reaction c) Redox reaction d) Reduction reaction Answer: c
Depositing a metal layer on another surface using electricity is called: a) Electroplating b) Galvanisation c) Rusting d) Crystallisation Answer: a
During photosynthesis, oxygen is released due to: a) Hydrolysis of carbohydrates b) Photolysis of water c) Reduction of CO₂ d) Breakdown of chlorophyll Answer: b
In the reaction ZnO + C → Zn + CO, carbon acts as a: a) Acid b) Base c) Reducing agent d) Oxidising agent Answer: c
The process of rust formation on iron is known as: a) Rusting b) Crystallisation c) Shoveling d) Spading Answer: a
Oxidation involves: a) Loss of protons b) Loss of electrons c) Loss of neutrons d) Gain of electrons Answer: b
Browning of pages in old books is due to: a) Frequent use b) Lack of air c) Dust accumulation d) Oxidation of cellulose Answer: d
Iron rusts in air when both are present: a) Carbon dioxide and moisture b) Water and paint c) Oxygen and grease d) Oxygen and moisture Answer: d
Rusting of iron: a) Decreases its weight b) Increases its weight c) Has no effect on weight d) Is unpredictable Answer: b
Iron rusts most rapidly in: a) Rainwater b) Distilled water c) Seawater d) River water Answer: c
The metal used for galvanising iron is: a) Zinc b) Chromium c) Lead d) Antimony Answer: a
Applying a zinc coat to prevent rusting is called: a) Galvanization b) Reduction c) Corrosion d) Calcination Answer: a
