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REDOX REACTION
Number of moles of K2Cr2O7 reduced by one mole of Sn2+ ions is…
K2Cr2O7 + Sn2+ → Sn4+ + Cr3+
[Haryana CEET 2000]
(a) 1/3
(b) 3
(c) 1/6
(d) 6
How many electrons are involved in oxidation by KMnO4 in basic medium ?
[Orissa JEE 2003]
(a) 1
(b) 2
(c) 5
(d) 3
When KMnO4 acts as an oxidising agent and ultimately forms [MnO4]–2
MnO2, Mn2O3, Mn+2 then the number of electrons transferred in each case
respectively is…
[AIEEE 2002]
(a) 4, 3, 1, 5
(b) 1, 5, 3, 7
(c) 1, 3, 4, 5
(d) 3, 5, 7, 1
The value of x in the partial redox equation…MnO4– + 8H+ + xe– Mn2+
+4H2O is
(a) 5
(b) 3
(c) 1
(d) 0
2MnO4– + 5H2O2 + 6H+ → 2 Z + 5 O2 + 8H2O. In this reaction Z is…
[RPMT 2002]
+2
(a) Mn
(b) Mn+4
(c) MnO2
(d) Mn
What is ‘A’ in the following reaction 2Fe3+(aq) + Sn2+(aq) → 2Fe2+(aq) +A…
[MP PET 2003]
3+
(a) Sn (aq)
(b) Sn4+(aq)
(c) Sn2+(aq)
(d) Sn
For the redox reaction… MnO4– + C2O4–2 + H+ → Mn2+ + CO2 + H2O
The correct coefficients of the reactants for the balanced reaction are…
[IIT 1988, 92; BHU 1995; CPMT 1997; RPMT 1999;DCE 2000; MP PET 2003]
MnO4–
C2O42–
H+
MnO4–
C2O42–
H+
(a)
2
5
16 (b)
16
5
2
(c)
5
16
2 (d)
2
16
5
Which of the following is a redox reaction
[AIEE 2002]
(a) NaCl + KNO3 → NaNO3 + KCl
(b) CaC2O4 + 2HCl → CaCl2 + H2C2O4
(c) Zn + 2AgCN→ 2 Ag +Zn(CN)2
(d) Mg(OH)2 + 2NH4Cl → MgCl2 + 2NH4OH
Which of the following reaction is a redox reaction
[MP PET 2003]
(a) P2O5 + 2H2O→ H4P2O7
(b) 2AgNO3 + BaCl2 → 2AgCl + Ba(NO3)2
(c) BaCl2 + H2SO4 → BaSO4 + 2HCl
(d) Cu + 2AgNO3 → 2Ag + Cu(NO3)
Redox Reactions / 4_3_A
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2
In the balanced chemical reaction,
[AIIMS 2005]
–
–
+
IO3 + aI + bH → c H2O + d I2
a, b, c and d respectively correspond to
(a) 5, 6, 3, 3
(b) 5, 3, 6, 3
(c) 3, 5, 3, 6
(d) 5, 6, 5, 5
The number of moles of KMnO4 reduced by one mole of KI in alkaline medium
is…
[CBSE PMT 2005]
a KMnO4 + b KI + c H2O → d MnO2 + e KOH + f KIO3
(a) One fifth
(b) Five
(c) One
(d) Two
The oxidation number of sulphur in S8, S2F2, H2S respectively, are
(a) 0, +1 and–2
(b) +2, +1 and –1
(c) 0, +1 and +2
(d) –2, +1 and –2
In the redox reaction.
[DUMET 2009]
xKMnO4 +NH3 
→ yKNO3 + MnO2 + KOH + H2O
(a) x = 4, y = 6
(b) x = 3, y = 8
(c) x = 8, y = 6
(d) x = 8, y = 3
A mole of N2H4 loses ten moles of electrons to form a new compound Y. Assuming
that all the nitrogen appears in the new compound ,what is the oxidation state of
nitrogen in Y? (there is no change in the oxidation number of hydrogen)
(a) − 1
(b) − 3
(c) +3
(d) +5
When copper is treated with a certain concentration of nitric acid, nitric oxide and
nitrogen dioxide are liberated in equal volumes according to the equation,
x Cu + y HNO3 → Cu(NO3)2 + NO + NO2 + H2O. The coefficients of x and y are
(a) 2 and 3
(b) 2 and 6
(c) 1 and 3
(d) 3 and 8
Oxidation number of N and S in (NH4)2S2O8 is
(a) 3− and +6
(b) 1+ and 2−
(c) 3+ and 8
(d) 3+ and 6−
The oxidation number of phosphorus in Ba(H2PO2)2 is :
(a) +3
(b) +2
(c) +1
(d) −1
A compound contains atoms X,Y, and Z . The oxidation number of X is +3, Y is +5 and
Z is -2 . The possible formula of the compound is
(a) XYZ2
(b) Y2(XZ3)2.
(c) X3(YZ4)3
(d) X3(Y4Z)2
Which of the following reaction is a redox reaction ?
(a) H2SO4 with NaOH
(b) Nitrogen oxides from nitrogen and oxygen by lightning
(c) In atmosphere, formation O3 from O2 by lightning
(d) Evaporation of H2O
Redox Reactions / 4_3_A
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In the reaction , 3Br2 + 6 CO32− + 3 H2O → 5Br− + BrO3− + 6 HCO3−
(a) Bromine is oxidized and carbonate is reduced
(b) Bromine is neither reduced nor oxidized
(c) Bromine is reduced and water is oxidized
(d) Bromine is both reduced as well as oxidized
The values of x and y in the following redox reaction… x Cl2 + OH− → ClO3− + y Cl−
+ 3H2O are…
(a) x =2 , y =4
(b) x =5 , y =3
(c) x =3 , y =5
(d) x = 4 , y =2
The value of ‘n’ in the reaction
Cr2O72– +14H+ + nFe2+ → 2Cr3+ + nFe3+ + 7H2O will be
[MP PET 2008]
(a) 2
(b) 3
(c) 6
(d) 7
The compound which could not act both as oxidising as well as reducing agent is
[IIT Screening 1991]
(a) SO2
(b) MnO2
(c) Al2O3
(d) CrO
In which of the following compounds, is the oxidation number of iodine is
fractional
[BVP 2003]
(a) IF3
(b) IF2
−
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3
(c) I3
(d) IF7
The compound YBa2Cu3O7 which shows superconductivity has cooper in oxidation
state ……. Assume that the rare earth element Yttrium is in its usual +3 oxidation
state
[IIT 1994]
(a) 3/7
(b) 7/3
(c) 3
(d) 7
In a balanced equation H2SO4 +xHI→ H2S + yI2 + zH2O, the value of x, y, z are
[EAMCET 2003]
(a) x = 3, y = 5, z = 2
(b) x = 4, y = 8, z = 5
(c) x = 8, y = 4, z = 4
(d) x = 5,y = 3, z = 4
2–
MnO4 (3 mole) in neutral aqueous medium is disproportionate to…
[AIIMS 2003]
a MnO42− → b MnO4− + c MnO2
(a) 2 mole of MnO4– and 1 mole of MnO2
(b) 1 mole of MnO4– and 2 mole of MnO2
(a) 2/3 mole of MnO4– and 1/3 mole of MnO2
(b) 1/3 mole of MnO4– and 2/3 mole of MnO2
Which of the following reaction is not a redox reaction ?
[CPMT 1971, 78]
(a) 4 KClO3→ 3KCIO4 + KCl
(b) SO2 + 2H2S→ 2H2O + 3S
(c) BaO2 + H2SO4→ BaSO4 + H2O2
(d) 2BaO + O2 → 2BaO2
Redox Reactions / 4_3_A
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4
The following species will not exhibit disproportionation reaction
[AMU (Engg.) 2009]
–
(a) CIO
(b) CIO2–
(c) CIO3–
(d) CIO4–
The equivalent weight of KIO3 in the reaction…
[MP PMT 2004]
a Cr(OH)3 + b OH− + c KIO3 → dCrO42– + e H2O + f KI is…
Mol.wt
(a) Mole wt.
(b)
6
Mol.wt
Mol.wt
(c)
(d)
2
3
In acidic medium, dichromatic ion oxidizes ferrous ion to ferric ion. If the gram
molecular weight of potassium dichromate is 294 grams, its gram equivalent weight is
………. Grams.
(a) 294
(b) 127
(c) 49
(d) 24.5
What is the equivalent mass of IO4– when it is converted into I2 in acid medium ?
(a) M/7
(b) M/6
(c) M/5
(d) M/4
For decolourization of 1 mole of acidified KMnO4, the moles of H2O2 required is ...
a KMnO4 + b H2O2 → c Mn2+ + d O2
(a) 1/2
(b) 3/2
(c) 5/2
(d) 7/2
In which of the following the oxidation number of oxygen has been arranged in
increasing order
(a) OF2 < KO2 < BaO2 < O3
(b) BaO2 < KO2 < O3 < OF2
BaO
<
O
<
OF
<
KO
(c)
2
3
2
2
(d) KO2 < OF2 < O3 < BaO2
In the balanced equation… 5 H2O2 + x ClO2 + 2 OH– → x Cl– + y O2 + 6 H2O
The reaction is balanced if
(a) x = 5 , y = 2
(b) x = 2, y = 5
(c) x = 4m y = 10
(d) x =5, y = 5
Number of moles of KMnO4 required to oxidize one mole of Fe(C2O4) in acidic medium is
x KMnO4 + y Fe(C2O4) → a Fe3+ + b CO2 + c Mn2+ + H2O
(a) 0.6
(b) 0.4
(c) 0.2
(d) 1.67
H+
2–
Cr2O7 + X
Cr3++ H2O +.......; .Here Cr2O72− oxidize reactant X, X in the above
reaction can not be...
2–
2–
(a) C2O4
(b) SO4
2–
2+
(c) S
(d) Fe
Equivalent mass of oxidizing agent in the reactions,
SO2 + 2H2S → 3 S + 2H2O is
(a) 32
(b) 64
(c) 16
(d) 8
The equivalent weight of MnSO4 is half of its molecular weight when it is converted to:
(a) Mn2O3
(b) MnO2
(c) MnO4
(d) MnO42-
Redox Reactions / 4_3_A
40.
5
The number of moles of KMnO4 that will be needed to react with one mole of oxalic
acid in acidic in acidic medium is… a KMnO4 + b H2C2O4 → c Mn2+ + d CO2 + H2O
(a) 2
(b) 5
(c) 2/5
(d) 3/5
Redox Reactions / 4_3_A
4
REDOX REACTION
Paper Code : 4_3_A
Chapter
:4
Std
: 11th Sem-I
a b
6
c
Name
Batch
School
d
:−
:−
:−
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Redox Reactions / 4_3_A