Which of the following substances is the anode in the dry Leclanche cell?
Consider the reaction represented by the equation: 2H2SO4(aq) + C(s) → 2H2O(l) + 2SO2(aq) + CO2(aq). H2SO4 is acting as
an oxidizing agent
a reducing agent
a sulphonating agent
Which of the following oxides of nitrogen has oxidation number of +1?
In dry Leclanche cell, manganese (IV) oxide acts as
a reducing agent
Oxidation takes place at the electrolysis because the anode
is deficient in electrons
is deficient in protons
has excess electrons
has attraction for positive ions
Calculate the quantity of electricity passed when 0.4A flows for 1 hour 20 minutes through an electrolytic cell?
Which of these cell notations is the correct representation of Daniel cell?
Zn(s) / Zn2+(aq) || Cu2+/Cu(s)
Cu(s) / Cu2+(aq) || Zn2+(aq) / Zn(s)
Zn2+(aq) / Zn(s) || Cu(aq) / Cu(s)
Cu2+(aq) / Cu(s) || Zn(s) /Zn2+(aq)(
Which species undergo reduction in the reaction represented by the equation below?
H2S(aq) + 2FeCl3(aq) → S(s) + 2HCl(aq) + 2FeCl2(aq)
What is the oxidation number chromium in K2CrO4?
What is the product formed at the cathode during the electrolysis of concentrated sodium chloride solution using carbon electrodes?
Electrolysis is applied in the following processes except
extraction of aluminium
extraction of iron
purification of copper
The oxidation number of iodine in the iodate ion (IO3-) is
Consider the reaction: 2Al(s) + 6H+(aq) → 2Al3+(aq) + 3H2(g) . What is the total number of moles of electrons transferred from aluminium atoms to the hydrogen ions?
In the reaction represented by the equation:
5Fe2+(aq) + MnO-4(aq) + 8H+(aq) → 5Fe3+(aq) + Mn2+4(aq) + 4H2O(l). Which species is reduced?
In which of the following reactions is sulphur (IV) oxide acting as an oxidizing agent?
2HNO3(aq) + SO2(g) → H2SO4(aq) + 2NO2(g)
2KMnO4(aq) + 5SO2(aq) + 2H2O(l) → K2SO4(aq) + MnSO4(aq) + 2H2SO4(aq)
FeCl3(aq) + SO2(g) + 2H2O(l) → FeCl2(aq) + 2HCl(g) + H2SO4(aq)
2H2S(g) + SO2(g) → 2H2O(l) + 3S(s)
Which of the following equations represent a redox reaction?
Pb(NO3)2(aq) + 2HCl → PbCl3 + 2HNO3(aq)
H2S(g) + Cl2(g) → 2HCl(g) + S(s)
AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNO3(aq)
BaCl2(aq) + K2SO4(aq) → BaSO4(s) + 2KCl
The main difference between a primary cell and a secondary cell is that the primary cell
The primary is an electrolytic cell but the secondary is not
cannot be recharged the secondary cell can
can be recharged but the secondary cell cannot
contains the electrodes but the secondary cell does not
What is the reducing agent in the reaction represented by the following equation?
Fe3+(aq) + H2S(g) → 2Fe2+(aq) + 2H+(aq) + S(s)
The reaction that takes place at the cathode when a aqueous solution of NaCl is electrolysed using carbon electrodes is
2H-(aq) + 2e- → H2(g)
Na+(aq) + e- → Na(s)
4OH → 2H2O2(l) + O2(g) + 4e-
2Cl- → Cl2(g) + 2e-
Consider the cell represented below.
Zn/Zn2+(aq) // Cu2+(aq)/Cu(s) .Which of the following statements is correct about the cell?
Zn is oxidized to Zn2+
Cu is oxidized to Cu2+
It is an electrolytic cell
Each single line represents a salt bridge
Consider the following electronegativity values:
Which is the change in the oxidation number of of I- in the reaction represented by the following equation?
5I-(aq) + 6H+(aq) + 10-3(aq) → 3I2(g) + 3H2O(l)
-5 to -3
-1 to 0
+5 to +3
-1 to +2
Consider the electrochemical cell represented below. Zn(s)/Zn2+(aq)//Cu2+(aq)/Cu(s) .Which of the following equations describes the reaction occuring in the cell?
Cu(s) + Zn2+(aq) → Cu2+(aq)
Cu(s) + Zn2+(s) → Cu2+(aq) + Zn2+(aq)
Zn(s) + Cu2+(aq) → Zn2+(s) + Cu(s)
Zn2+(aq) + Cu2+(aq) → Zn(s) + Cu(s)
Which of the metals is most likely extracted by electrolysis of its fused chloride?
Which of the following statements is/are correct about tin plating?
I. The electrolyte must be a soluble salt of tin
II The object to be plated is made the cathode
III The anode is made of tin
IV The negative electrodes dissolves
I and II only
I, II, III only
I, II and IV only
What is the product at the positive electrodes
Determine the amount of electrons needed to deposit 6.4g of copper during the electrolysis of copper (II) tetraozosulphate (VI) solution [Cu = 64]
The equation for the reaction at the anode during the electrolysis of concentrated sodium chloride solution is
2Cl-(aq) → Cl2(g) + 2e-
4OH-(aq) → 2H2O(l) + O2(g) + 4e-
Na+(aq) + e- → Na(s)
2H+(aq) + 2e- → H2(g)
Consider the following equation: Cr2O72-(aq) + 14H+(aq) + 6e- → 2Cr3+(aq) + 7H2O(l). The oxidation number of chromium changes from
-2 to +3
-2 to +6
+6 to +3
+7 to +6
Which of the following ions require the largest quantity of electricity for discharge at an electrode?
2.0 mole of Q3+
2.5 mole of R2+
3.0 mole T-
4.0 mole of Y-
If two metallic ions of the same concentration migrate to a graphite cathode, the one that would be preferentially discharged is the one that has the
lower electrical charge
greater stability in solution
stronger tendency to accept electrons
When conentrated sodium chloride is electrolysed using inert electrodes, the products are
oxygen and hydrogen
hydrogen and chlorine
sodium and oxygen
sodium and chlorine
What is the oxidation number of nitrogen in Al(NO3)3?
What is oxidized in the reaction represented by the following equation?
3Cu + 8HNO3 → 3Cu(NO3)2 + 2NO + 4H2O
Which of the following ssubstances decomposes when an electric current is passed through it?
A concentrated solution containing H+, Cu2+, OH- and Cl- was electrolyzed using platinum electrodes. Which of the ions will be discharged at the cathode?
In the electrolysis of CuSO4 using copper electrodes, the reaction of the anode is
discharge of SO42-
discharge of OH-
dissoution of copper electrodes
evolution of oxygen
A feasible cell was constructed by joining the two half celss thus:
Cu2+(aq) + 2e- → Cu(s) Eo = +0.34V; Zn2+(aq) + 2e- → Zn(s) Eo = -0.76V. What is the standard of e.m.f of the cell?
In which of the following is the oxidation number of sulphur equal to -2?
An iron nail placed in solution of copper (II) tetraoxosulphate (VI) is soon covered with a deposit of copper. Which of the following equations represents the reaction?
Fe2+(aq) + Cu(s) → Fe3+(aq) + Cu2+(aq)
Fe2+(aq) + Cu(s) → Fe(aq) + Cu2+(aq)
Fe(s) + Cu2+(aq) → Fe2+(aq) + Cu2+(aq)
Fe(s) + Cu2+(aq) → Fe2+(aq) + Cu(s)
0.10 mole dm-3 NaCl conducts electricity better than o.10 mole dm-3 CH3COOH because the solution of NaCl
contains more ions
is neutral to litmus
has a lower molar mass
has a higher pH
Which of the following occurs when a solution of CuSO4 is electrolysed using copper electrodes?
The cathode becomes coated with copper
Both electrodes gain electrons
The blue colour of the solution fades gradually
The anode increases in mass
Which of the following is not correct about oxidation number convention? The oxidation number of a/an
element in the free state is zero
monoatomic ion is equal to its charge
alkali metals like sodium in its compound is +1
atom of a diatomic molecule is +2
When dilute copper (II) chloride solution is electrolysed, the reaction at the cathode is represented by the equation:
Cu → Cu2+ + 2e-
Cu2+ + 2e- → Cu
4OH- + 4e- → O2 + 2H2O
2Cl- → Cl2 + 2e-
The set-up shown in the diagram represents a/an
The bulb in the set-up will not light if K is
Molten sodium chloride
A metal which can be used as sacrificial anode for preventing corrosion of iron pipe is
What is the function of sulhpur (IV) oxide in the reaction represented by the following equation?
SO2(g) + 2H2S(g) → 3S(g) + 2H2O(l)
Which of the following will produce oxygen and hydrogen during its electrolysis using plantinum electrode?
Aqueous copper (II) tetraoxosulphate (VI)
Dilute sodium chloride solution
Concentrated hydrochloric acid
Dilute copper (II) chloride solution
How many electrons are removed from Cr2+ when it is oxidized to CrO42-?
Which of the following is/are manufactured by electrolysis?
I and II
III and IV
I, II and III
I, II, III and IV
Which of the following will migrate to the cathode during electrolysis?
Tetraoxosulphate (VI) ions
Trioxonitrate (V) ions
The common feature of reaction at the anode is that
electrons are consumed
oxidation is involved
ions are reduced
the electrodes dissolves
the electrolyte is diluted
Which of the following metals is not extracted by electrolysis?
Amphoteric oxides are oxides which
react with water to form acids
react with water to form alkali
show neither acidic or basic properties
react with both acids and alkalis
contain high proportion of oxygen
In which of the following compounds is the oxidation number of nitrogen equal to +3?
Which of the following statements is not correct about electrolysis?
Reduction occurs in the anode
Anions migrate to the anode
Positive ions migrate to the cathode
Concentration affects the discharge of ions
Electrolytes conducts electric current
When acidified KmnO4 solution is decolorised by ethene, the gas the acts as
a straight-chain hydrocarbon
a saturated hydrocarbonate
a reducing agent
a dehydrating agent
an oxidizing agent