IISER Chemistry - Oxidation and Reduction
Exam Duration: 45 Mins Total Questions : 30
Oxidation is also termed as
- (a)
electronation
- (b)
deelectronation
- (c)
protonnation
- (d)
deprotonnation
In the given reaction \(2Fe{ Cl }_{ 3 }+Sn{ Cl }_{ 2 }\longrightarrow 2Fe{ Cl }_{ 2 }+Sn{ Cl }_{ 4 }\) the substance which is reduced is
- (a)
Sn2+
- (b)
Fe3+
- (c)
Fe2+
- (d)
Sn4+
In the reaction \(2Mn{ O }_{ 4 }^{ - }+5{ C }_{ 2 }{ O }_{ 4 }^{ 2- }+16{ H }^{ + }\longrightarrow 2M{ n }^{ 2+ }+8{ H }_{ 2 }O+A\) the product A is
- (a)
CO2
- (b)
C
- (c)
CO
- (d)
\(C{ O }_{ 3 }^{ 2- }\)
In oxygen difluoride the oxidation number of oxygen is
- (a)
-2
- (b)
-1
- (c)
+2
- (d)
+1
In which of the following pairs of compounds, the oxidation number of chromium is +6?
- (a)
\([Cr\left( { NH }_{ 3 } \right) _{ 6 }]^{ 3+ }andCrC{ l }_{ 3 }\)
- (b)
\([Cr(CN)_{ 6 }]^{ 3- }andCr({ NO }_{ 3 })_{ 3 }\)
- (c)
\([Cr{ Cl }_{ 6 }]^{ 2- }\quad and\quad { Cr }_{ 2 }{ O }_{ 3 }\)
- (d)
\({ Cr }{ O }_{ 2 }C{ l }_{ 2 }\quad and\quad Cr{ O }_{ 3 }\)
The equivalent weight of KMnO4 in neutral medium is
- (a)
31.6
- (b)
158
- (c)
52.66
- (d)
26.33
Equal volumes each of 1M solution containing FeCl3 and SnCl2 are mixed together, the resultant solution will contain
- (a)
Fe2+, Sn2+, Sn4+
- (b)
Fe2+, Fe3+, Sn2+
- (c)
Fe2+, Fe3+, Sn4+
- (d)
Sn2+, Sn4+, Fe3+
Which one of the following equations represents the change \(Mn{ O }_{ 4 }^{ - }\longrightarrow Mn{ O }_{ 2 }\) in basic solution?
- (a)
\(Mn{ O }_{ 4 }^{ - }+4{ H }_{ 2 }O+3e\longrightarrow Mn{ O }_{ 2 }+2{ H }_{ 2 }O+{ OH }^{ - }\)
- (b)
\(Mn{ O }_{ 4 }^{ - }+4{ OH }^{ - }\longrightarrow Mn{ O }_{ 2 }+2{ H }_{ 2 }O+{ 3e }\)
- (c)
\(Mn{ O }_{ 4 }^{ - }+4{ H }^{ + }-3e\longrightarrow Mn{ O }_{ 2 }+2{ H }_{ 2 }O\)
- (d)
\(Mn{ O }_{ 4 }^{ - }+4{ H }^{ + }\longrightarrow Mn{ O }_{ 2 }+2{ H }_{ 2 }O+3e\)
In a redox reaction, the oxidant
- (a)
shares electrons with the reductant
- (b)
gains electrons from the reductant
- (c)
transfers electrons to the reductant
- (d)
neither shares nor transfers electrons to the reductant
In the reaction \(Mn{ O }_{ 4 }^{ - }+5{ Fe }^{ 2+ }+8{ H }^{ + }\longrightarrow Mn^{ 2+ }+5{ Fe }^{ 3+ }+4{ H }_{ 2 }O\) the oxidation number of
- (a)
Mn decreases by - 5 only
- (b)
Fe increases by - 1 only
- (c)
Mn decreases by + 5 and that of Fe increases by -1
- (d)
Mn decreases by + 5 and that of Fe increases by + 1
The reductant
- (a)
adds electrons
- (b)
gets reduced
- (c)
loses electrons
- (d)
NONE OF THE ABOVE
When copper turnings are added to AgNO3 solution, the solution becomes blue because
- (a)
Cu is oxidised to Cu2+
- (b)
Cu2+ is reduced to Cu+
- (c)
Cu2+ is reduced to Cu
- (d)
Cu is oxidised to Cu+
The oxidation number of iodine ranges from
- (a)
- 1 to + 7
- (b)
- 1 to - 7
- (c)
+ 1 to + 7
- (d)
-1 to + 1
In the reaction \({ 2I }^{ - }+{ Cl }_{ 2 }\longrightarrow { I }_{ 2 }+2C{ l }^{ - }\) the reductant is
- (a)
I-
- (b)
Cl2
- (c)
I2-
- (d)
Cl-
In which one of the following reactions H2O2 acts as an oxidising agent?
- (a)
\({ 2I }^{ - }+2{ H }^{ + }+{ H }_{ 2 }{ O }_{ 2 }\longrightarrow { I }_{ 2 }+2{ H }_{ 2 }{ O }\)
- (b)
\({ Ag }_{ 2 }O+{ H }_{ 2 }{ O }_{ 2 }{ \longrightarrow 2Ag+{ H }_{ 2 }{ O } }+{ O }_{ 2 }\)
- (c)
\(2Mn{ O }_{ 4 }^{ - }+6{ H }^{ + }+5{ H }_{ 2 }{ { O }_{ 2 } }{ \longrightarrow 2M{ n }^{ 2+ }+{ 8H }_{ 2 }{ O } }+{ 5O }_{ 2 }\)
- (d)
\({ O }_{ 2 }+2{ H }_{ 2 }{ O }_{ 2 }{ \longrightarrow { 2O }_{ 2 }+{ 2H }_{ 2 }{ O } }\)
CO2 is
- (a)
an oxidising agent
- (b)
a reducing agent
- (c)
a dehydrating agent
- (d)
a bleaching agent
Maximum oxidation state of phosphorus is found in
- (a)
H3PO4
- (b)
H4P2O7
- (c)
H3PO5
- (d)
H4P2O6
In the reaction \(3{ Br }_{ 2 }+6{ CO }_{ 3 }^{ 2- }+3{ H }_{ 2 }O\longrightarrow 5{ Br }^{ - }+{ BrO }_{ 3 }^{ - }+6HC{ O }_{ 3 }^{ - }\)
- (a)
bromine is reduced and carbonate is oxidised
- (b)
bromine is oxidised and carbonate is oxidised
- (c)
bromine is reduced as well as oxidised
- (d)
bromine is neither reduced nor oxidised
The oxidation number of C in CH4 , CH3 Cl, CH2Cl2 , CHCl3 are CCl4 is respectively
- (a)
0, 2, -2, 4, 4
- (b)
2, 4, 0, -2, -4
- (c)
-4, -2, 0, 2, 4
- (d)
4, 2, 0, -2, -4
For the following reaction in the acidic solution \(Mn{ O }_{ 4 }^{ - }+8{ H }^{ + }+5e\longrightarrow Mn^{ 2+ }+4{ H }_{ 2 }O\) which of the following gives the oxidation numbers of the manganese on each side of the equation.
- (a)
+ 4 to + 2
- (b)
-1 to + 2
- (c)
+ 7 to + 5
- (d)
+ 7 to + 2
The oxidation state of chemical carbon is
- (a)
0
- (b)
1
- (c)
2
- (d)
3
The charge on coblt in \([Co\left( { CN }_{ 6 } \right) ]^{ -3 }\) is
- (a)
- 3
- (b)
- 6
- (c)
+ 3
- (d)
+ 6
Which one of the following is the strongest oxidising agent?
- (a)
F2
- (b)
Cl2
- (c)
Br2
- (d)
I2
In which of the following compounds iron has the lowest oxidation state?
- (a)
FeSO4 (NH4)2SO4.6H2O
- (b)
K4Fe(CN)6
- (c)
K3 Fe (CN)6
- (d)
Fe(CO)5
Oxidation numbr of Fe in \({ K }_{ 3 }Fe({ CN })_{ 6 }\) is
- (a)
+ 1
- (b)
+ 2
- (c)
+ 3
- (d)
+ 4
If three electrons are lost by a metal ion M+3 , its final oxidation number would be
- (a)
zero
- (b)
- 3
- (c)
+ 6
- (d)
NONE OF THESE
The colour of K2Cr2O7 changes from red orange to lemon orange yellow on treatment with aqueous KOH because of
- (a)
reduction of Cr (VI) to Cr (III)
- (b)
formation of chromium hydroxide
- (c)
conversion of dichromate ion to chromate
- (d)
oxidation of potassium hydroxide to potassium peroxide
A 2.5 mol of hydrazine N2H4 loses 25 mole of electrons being converted to a new compound X. Assume that all of the nitrogen appeas in the new compound, what is the oxidation state of nitrogen in compound X?
- (a)
- 1
- (b)
- 2
- (c)
+ 3
- (d)
+ 4
When KMnO4 acts as an oxidising agent and ultimately forms MnO4-1, MnO2, Mn2O3, Mn2+ then the number of electrons transferred in each case respectively is
- (a)
4 , 3, 1, 5
- (b)
1, 5, 3, 7
- (c)
1, 3, 4, 5
- (d)
3, 5, 7, 1
Which of the following is a redox reaction?
- (a)
\(Nacl+KN{ O }_{ 3 }\longrightarrow Na{ NO }_{ 3 }+Kcl\)
- (b)
\(Ca{ C }_{ 2 }{ O }_{ 4 }+2HCl\longrightarrow CaC{ l }_{ 2 }+{ H }_{ 2 }{ C }_{ 2 }{ O }_{ 4 }\)
- (c)
\(Mg\left( OH \right) _{ 2 }+2N{ H }_{ 4 }Cl\longrightarrow Mg{ Cl }_{ 2 }+2N{ H }_{ 4 }OH\)
- (d)
\(Zn+2AgCN\longrightarrow 2Ag+Zn\left( CN \right) _{ 4 }\)