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WorksheetsRedox
Total questions: 15
Worksheet time: 23mins
What is the oxidation of sulfur in Na2SO3?
0
+2
+4
-4
Which reaction is an example of a redox reaction?
2SO2 + O2 → 2SO3
Ag+ + Cl- → AgCl
CuO + H2SO4 → CuSO4 +H2O
H+ + OH- → H2O
Which of the following is involved in reduction?
loss of oxygen
loss of hydrogen
loss of electrons
increase in oxidation state
In which of the following changes is the first substance reduced?
KCl into KClO3
Br2O into Br2
HCl into Cl2
Na2SO3 into Na2SO4
A reducing agent ______________________.
decreases in oxidation state
is reduced at the end of a reaction
gains oxygen
accepts electrons
Which compound, in aqueous solution, when added to aqueous iron(II) sulfate, takes part in a redox reaction?
acidified potassium manganate(VII)
ammonia
copper(II) nitrate
sodium hydroxide
Substance X changes aqueous potassium iodide from colourless to brown and changes aqueous potassium manganate(VII) from purple to colourless. Which statement correctly describes X?
It is an oxidising agent only.
It is a reducing agent only.
It is an oxidising agent and a reducing agent.
It is neither an oxidising agent nor a reducing agent.
A drop of solution S turns acidified potassium dichromate(VI) to green chromium(III) ion.
What does solution S behave as?
an acid
an oxidising agent
a reducing agent
neither oxidising nor reducing agent
Ozone gas is a colourless and a powerful oxidising agent. What colour change would you expect to see when ozone is bubbled through aqueous potassium iodide?
colourless to brown
brown to colourless
purple to brown
purple to colourless
State the oxidation state of Cr in CrO4-.
(a)
State the oxidation state of Cr in ZnCrO4.
(a)
Tungsten can be extracted from its oxide, WO3, by heating it with carbon monoxide. Carbon dioxide is produced as shown below.
WO3+ 3CO → W + 3CO2
Explain, in terms of oxidation state, why tungsten in tungsten oxide has been reduced.
In a reaction, MnO4- is converted to Mn2+. Explain, in terms of electron transfer, if manganese (Mn) is oxidised or reduced.
Ammonia reacts with chlorine as shown:
2NH3 + 3Cl2 → N2 + 6HCl
State the oxidising agent.
Explain your answer.
Describe how you would carry out a test for a reducing agent. State your observation if the test for the reducing agent is positive.
