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NEET Chemistry MCQ
Redox Reactions And Electro Chemistry Mcq
Quiz 4
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Q.1
The number of electrons required to balance the following equation. NO3- + 4H+ + e- → 2H2O + NO is [ IIT Screening Test 1991]
0%
a)5
0%
b) 4
0%
c)3
0%
d)2
Explanation
Correct equation is NO3- +4H+ + 3e- → 2H2O + NO Answer: (c)
Q.2
The equivalent weight of Mohr's salt, FeSO4 .(NH4)2SO4 . 6H2O is equal to ..[DPMT 1994]
0%
a) Its molecular weight
0%
b) Atomic weight
0%
c)Half-its molecular weight
0%
d)one third its molecular weight
Explanation
Answer: (a)
Q.3
The oxide which cannot act as reducing agent is ..[CBSE PMT 1995]
0%
a) SO2
0%
b) NO2
0%
c)CO2
0%
d)ClO2
Explanation
In CO2 oxidation state is +4 and now can not be increased and hence does not act as reducing agent Answer:(c)
Q.4
Which of the following is a redox reaction ? [ CBSE PMT 1997]
0%
a) H2SO4 with NaOH
0%
b) In atmosphere, O3 from O2 by lighting
0%
c) Nitrogen oxides form nitrogen and oxygen by lighting
0%
d) Evaporation of H2O
Explanation
in option 'c' oxidation number of Nitrogen increased from 0 to +2 and oxidation number of oxygen is decreased from 0 to -2 Answer: (c)
Q.5
C2H6 (g) + nO2 → CO2(g) + H2O(l) In this equation, ratio of the coefficients of CO2 and H2 is [ KCET 1992]
0%
a)1:1
0%
b) 2:3
0%
c)3:2
0%
d)1:3
Explanation
The balance equation is 2C2H6 + 5O2 → 4CO2 + 6H2ORatio of the coefficients of CO2and H2O is 4:6 or 2:3Answer: (b)
Q.6
In which of the following compounds, the oxidation number of iodine is fractional? [ BHU 1994]
0%
a) If7
0%
b) I3-
0%
c)IF5
0%
d)IF3
Explanation
Let x be oxidation number of I thenfor I3- , 3x=-1 ∴ x=-1/3Answer: (b)
Q.7
In the reaction2FeCl3 + H2S → 2FeCl2 + 2HCl + S... [MLNR 1996]
0%
a) FeCl3 acts as an oxidizing agent
0%
b) Both H2S and FeCl2 are oxidizied
0%
c)FeCl3 is oxidised while H2S is reduced
0%
d)H2S acts as an oxidising agent
Explanation
In equation oxidation number of Fe reduce to+1 from +3 thus e3 acts as oxidizing agent while H2S acts as reducing agent Answer:(a)
Q.8
Oxidation number of carbon in CH2Cl2 is [AMU 19997]
0%
a) -4
0%
b) +4
0%
c) 0
0%
d) -2
Explanation
Answer: (c)
Q.9
In the chemical reaction K2Cr2O7 + a H2SO4 + bSO2 → K2SO4 + Cr2(SO4)3 + cH2O a, b, c are [BHU 1994]
0%
a)1, 3, 1
0%
b) 4, 1, 4
0%
c)3, 2, 3
0%
d)2, 1, 2
Explanation
Answer: (a)
Q.10
Phosphorus has the oxidation state of +3 in [ CBSE PMT 1994]
0%
a) Phosphorous acid
0%
b) Orthophosphorous acid
0%
c) Hypophosphorous acid
0%
d)Metalphosphoric acid
Explanation
Answer: (a)
Q.11
In which of the following compounds, nitrogen has an oxidation state of -1? [ AIIMS 1994]
0%
a) N2O
0%
b) NO2-
0%
c)NH2OH
0%
d)N2H4
Explanation
Answer:(c)
Q.12
The violent reaction between sodium and water is an example of [ CPMT 1987]
0%
a) Reduction
0%
b) Oxidation
0%
c) Redox reaction
0%
d) Neutralization reaction
Explanation
Answer: (c)
Q.13
The oxidation number of phosphorus in Ba(H2PO2)2 is ..[IIT 1990]
0%
a)+3
0%
b) +2
0%
c)+1
0%
d)-1
Explanation
Let oxidation number of P be x Oxidation number of Ba=2; H=1; O=-22+2[2×(1) + x +2×(-2)]=0 ∴ x=+1Answer: (c)
Q.14
Formula weight divided by the change in oxidation number gives [..[BHU 1994]
0%
a) equivalent weight of an oxidant
0%
b) equivalent weight of the reductant
0%
c)the number of electrons gained in the reaction
0%
d)the equivalent weight of the oxidant or reductant
Explanation
Answer: (d)
Q.15
Which of the following involves transfer of five electrons? [ JIPMER 1994]
0%
a) MnO4- → Mn2+
0%
b) CrO4- → Cr3+
0%
c)MnO43- → MnO2
0%
d)Cr2O72- → 2Cr3+
Explanation
Answer:(a)
Q.16
When KMnO4 reacts with acidified FeSO4.. [ MP PET 1996]
0%
a) Only FeSO4 is oxidised
0%
b) Only KMnO4 is oxidised
0%
c) FeSO4 is oxidised and KMnO4 is reduced
0%
d) None of the above
Explanation
In Acidic medium KMnO4 acts as oxidising agent ,thus get reduced and FeSO4 gets oxidised Answer: (c)
Q.17
One of the following has both positive and negative oxidation states..[ DPMT 1994]
0%
a) F
0%
b) Cl
0%
c)He
0%
d)Na
Explanation
Cl can have both negative (-1) and positive ( +1, +3, +5 or +7) oxidation statesAnswer: (b)
Q.18
The equivalent weight of MnSO4 is half its molecular weight when it is converted into [ CPMT 1992]
0%
a)Mn2O3
0%
b) MNO4-
0%
c)MnO2
0%
d)MnO42-
Explanation
Equivalent weight of the substance is half of the molecular weight Since oxidation number of Mn is reduced by two MnO2 → MnSO4 Answer: (c)
Q.19
Which of the following behaves as both oxidizing and reducing agents [AFMC 1995]
0%
a) H2SO4
0%
b) SO2
0%
c)H2S
0%
d)HNO3
Explanation
S in SO2 has an oxidation number +4 S can have lowest oxidation number (-2) and highest oxidation number (+6) thus SO2 can act as oxidising as well as reducing agent Answer:(b)
Q.20
In which of the following reactions, there is no change in valency? [ CBSE PMT 1994]
0%
a) 4KClO3 → 3KClO4 + KCl
0%
b) SO2 + 2H2S → 2H2O + 3S
0%
c)BaO2 + H2SO4 → BaSO4 + H2O2
0%
d)2BaO + O2 → 2BaO2
Explanation
In potion 'c' reaction , none of the element undergoes a change in oxidation numberAnswer: (c)
Q.21
In the following reaction, which is the species being oxidised? [ AMU 1997]2Fe3+a(aq) + 2I- (aq) → I2(aq) + 2Fe2+(aq)
0%
a)Fe3+
0%
b) I-
0%
c)I2
0%
d)Fe2+
Explanation
Answer:(b)
Q.22
KMnO4 oxidises oxalic acid in acidic medium. the number of CO2 molecules produced as per the balanced equation is ... [ EAMCET 1998]
0%
a) 10
0%
b) 8
0%
c) 6
0%
d) 3
Explanation
MnO4- + C2O- → Mn + CO2 After balancing above equation we get 2MnO4- + 5C2O4- +16H2O → 2Mn + 10CO2 Answer: (a)
Q.23
In which of the compound does manganese exhibit highest oxidation number? [ AFMC 1994]
0%
a)MnO2
0%
b) Mn3O4
0%
c)K2MnO4
0%
d)MnSO4
Explanation
Answer: (c)
Q.24
In the reaction between SO2 and O3, the equivalent weight of ozone is [ JIPMER 1994]
0%
a) the same as its molecular weight
0%
b) half the molecular weight
0%
c)one third of the molecular weight
0%
d)one-fourth of the molecular weight
Explanation
3SO2 + O3 → 3SO3 This reaction involves two -electron changes and hence equivalent is half its molecular weightAnswer: (b)
Q.25
Oxidation number of cobalt in KI[Co(CO)4] is ..[haryana CEET 1996]
0%
a)+1
0%
b)+3
0%
c)-1
0%
d)-3
Explanation
Answer:(c)
Q.26
SO2 acts as an oxidant when it reacts with [EAMCET 1987]
0%
a) Acidified KMnO4
0%
b) Acidified K2Cr2O7
0%
c) H2S
0%
d) Acidified C2H5OH
Explanation
With strong oxidising agents like KMnO45, K2Cr2O7 etc. SO2 acts as a reducing agent Answer: (c)
Q.27
Consider the reaction Zn + Cu2+ → Zn2+ + Cu With reference to the above, which one of the following is the correct statement? [] BIT 1991]
0%
a)Zn is reduced to Zn2+
0%
b) Zn is oxidised to Zn2+
0%
c)Zn2+ is oxidised to Zn
0%
d)Cu2+ is oxidised to Cu
Explanation
Answer: (b)
Q.28
Which of the following reactions depicts the oxidising property of SO2 [DPMT 1994]
0%
a) SO2 + H2O → H2SO3
0%
b) 2H2S + SO2 → 3S + 2H2O
0%
c)Cl2 + SO2 → SO2Cl2
0%
d)2MnO4- + 5SO2 +2H2O → 5SO4- + 2Mn2+ + 4H+
Explanation
in option 'b' SO2 acts as an oxidising agent and thus oxidises H2S to SAnswer: (b)
Q.29
Oxidation number of nitrogen in (NH4)2SO4 is [ CPMT 1996]
0%
a) -1/3
0%
b) -1
0%
c)+1
0%
d)-3
Explanation
Answer:(d)
Q.30
xMnO4- + yC2O42- + zH+ → Mn2+ +CO2 + H2O, the correct coefficient x, y and z are .. [ IIT 1992]
0%
a) 2, 5, 16
0%
b) 16, 5, 2
0%
c) 5, 16, 2
0%
d) 2, 16, 5
Explanation
Answer: (a)
0 h : 0 m : 1 s
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