Oxidation reduction (p. bahadur obj.) - Shailendra Kumar Chemistry

PHYSICAL CHEMISTRY
by: SHAILENDRA KR.
Classes at: -
SCIENCE TUTORIALS; Opp. Khuda Baksh Library, Ashok Rajpath, Patna
PIN POINT STUDY CIRCLE; House No. 5A/65, Opp. Mahual Kothi, Alpana Market, Patna
Topic: Oxidation & Reduction
01. Oxidation state of oxygen in H 2
O 2
is:
(a) –2 (b) –1
(c) +1 (d) +2
02. The oxidation number of phosphorus in Mg 2
P 2
O 7
is:
(a) +5 (b) -5
(c) +6 (d) -7
03. In CH 2
Cl 2
, the oxidation number of C is:
(a) -4 (b) +2
(c) Zero (d) +4
04. Which compound has oxidation number of carbon
equal to zero
(a) C 6
H 6
(b) CH 3
(c) C 2
H 4
(d) C 6
H 12
O 6
05. Oxidation state of +1 for phosphorus is found in:
(a) H 3
PO 3
(b) H 3
PO 4
(c) H 3
PO 2
(d) H 4
P 2
O 7
06. The oxidation number of sulphur in H 2
S 2
O 8
is:
(a) +2 (b) +6
(c) +7 (d) +14
07. Oxidation number of sulphur in Na 2
SO 4
is:
(a) +2 (b) +4
(c) +6 (d) -2
08. A compound contains atoms X, Y, Z. The oxidation
number of X is +2, Y is +5 and Z is -2. The possible
formula of the compound is:
(a) XY 1
Z 2
(b) Y 2
(XZ 3
) 2
(c) X 3
(YZ 4
) 2
(d) X 3
(Y 4
Z) 2
09. Oxidation number of carbon in KCN is:
(a) +2 (b) -2
(c) +1 (d) +3
10. The Oxidation number of Cr in [Cr(NH 3
) 4
Cl 2
] + is:
(a) +3 (b) +2
(c) +1
(d) Zero
11. Oxidation number of nitrogen in AgNO 3
is:
(a) +5 (b) -3
(c) +3 (d) -2
12. In which compound, oxygen has an oxidation state
of +2
(a) H 2
O 2
(b) H 2
O
(c) OF 2
(d) CO
13. The oxidation state of hydrogen in CaH 2
is:
(a) +1 (b) -1
(c) Zero (d) +2
14. Sulphur has the highest oxidation state in:
Meq. Approach
(a) SO 2
(b) SO 3
(b) H 2
SO 3
(d) H 2
S
15. In the conversion of Br 2
to BrO 3–
, the oxidation state
of bromine changes from:
(a) 0 to +5 (b) -1 to +5
(c) 0 to -3 (d) +2 to +5
16. In the reduction of dichromate by Fe(II), the number
of electrons involved per chromium atom is:
(a) 3 (b) 1
(c) 2 (d) 4
17. For reducing one mole of Fe 2+ ion to Fe, the number
of faraday of electricity is:
(a) 2 (b) 1
(c) 1.5 (d) 4
18. The number of mole of oxalate ions oxidised by one
–
mole of MnO 4
is:
(a) 1/5 (b) 2/5
(c) 5/2 (d) 5
19. Maximum oxidation state is present in:
–
(a) CrO 2
Cl 2
and MnO 4
(b) MnO 2
(c) [Fe(CN) 6
] 3– and [Co(CN) 6
] 3–
(d) MnO
20. When Sn (IV) chloride is treated with excess HCl,
the complex [SnCl 6
] 2– is formed. The oxidation state
of Sn in this complex is:
(a) +6 (b) -2
(c) +4 (d) -5
21. Oxidation state of oxygen atom in potassium
superoxide (KO 2
) is:
(a) -1/2
(b) Zero
(c) +1/2 (d) -2
22. When KMnO 4
is reduced with oxalic acid in acid
medium, the oxidation number of Mn changes from:
(a) +7 to +4 (b) +6 to +4
(c) +7 to +2 (c) +4 to +2
23. Oxidation number of chromium in K 2
Cr 2
O 7
is:
(a) +2 (b) +3
(c) +6 (d) -4
24. Chlorine has +1 oxidation state in:
(a) HCl (b) HClO 3
(c) Cl 2
O (d) ICl 3
25. Iodine has +7 oxidation state in:
(a) HIO 4
(b) H 3
IO 5

(c) H 5
IO 6
(d) All of these
26. Which reaction indicates the oxidising behaviour of
H 2
SO 4
(a) 2PCl 5
+ H 2
SO 4
––––→ 2POCl 3
+ 2HCl + SO 2
Cl 2
(b) 2NaOH + H 2
SO 4
––––→ Na 2
SO 4
+ 2H 2
O
(c) NaCl + H 2
SO 4
––––→ NaHSO 4
+ HCl
(d) 2HI + H 2
SO 4
––––→ I 2
+ SO 2
+ 2H 2
O
27. If three electrons are lost by a metal ion M 3+ , its final
oxidation number will be:
(a) Zero (b) +6
(c) +2 (d) +4
28. Oxidation number of N in N 3
H is:
(a) -3 (b) +3
(c) Zero (d) -1/3
29. The oxidation number of N in NH 3
is:
(a) -3 (b) +3
(c) Zero (d) 5
30. Oxidation number of S in S 2
Cl 2
is:
(a) +1 (b) +6
(c) Zero (d) -1
31. The oxidation number of Fe in K 4
Fe(CN) 6
is:
(a) +2 (b) +3
(c) +4 (d) +6
–
32. HCO 3
contains carbon in the oxidation state:
(a) +5 (b) +1
(c) +4
(d) Zero
33. In nitric oxide (NO) the oxidation state of N is:
(a) -2 (b) +1
(c) -1 (d) +2
34. In which of the following N has lowest oxidation
number
(a) NO (b) NO 2
(c) N 2
O (d) N 2
O 5
2–
35. Oxidation number of S in S 2
O 3
is:
(a) +2 (b) -2
(c) 4
(d) Zero
36. Oxidation number of Fe in K 3
[Fe(CN) 6
] is:
(a) +2 (b) +3
(c) +4 (d) +1
37. The maximum oxidation number of transition metals
may be:
(a) +4 (b) +6
(c) +8 (d) +10
38. Carbon is in the lowest oxidation state in :
(a) CH 4
(b) CCl 4
(b) CO 2
(d) CF 4
39. Oxidation state of oxygen is -1 in the compound :
(a) NO 2
(b) MnO 2
(c) PbO 2
(d) Na 2
O 2
40. In sodium hydride, oxidation state of sodium is:
(a) Zero (b) +1
(c) -1 (d) +2
41. In MgH 2
, Oxidation number of hydrogen is:
(a) -1 (b) +1
(c) -2 (d) +2
42. The oxidation number of iodine in IF 5
is:
(a) +5 (b) -5
(c) -1 (d) +1
43. What is the ox. no. of Mn in K 2
MnO 4
(a) +4 (b) +6
(c) +2 (d) +8
44. With which element oxygen shows positive oxidation
state in its compounds
(a) Na
(b) Cl
(c) N
(d) F
45. The oxidation number of Mn in MnO 2
is:
(a) +4 (b) +6
(c) +2 (d) -4
46. The oxidation number of P in KH 2
PO 2
is:
(a) +1 (b) +3
(c) -3 (d) +5
47. The oxidation number of Cl in KClO 3
is:
(a) +5 (b) -5
(c) +3 (d) -3
48. One mole of N 2
H 4
loses 10 mole of electrons to form
a new compound Y, Assuming that all nitrogen
appears in the new compound, what is the oxidation
number of nitrogen in Y (There is no change in the
oxidation state of hydrogen)
(a) -3 (b) +3
(c) +5 (d) +1
49. The reaction is balanced if,
5H 2
O 2
+ XClO 2
+ 2OH – ––––→ XCl – + YO 2
+ 6H 2
O
(a) X = 5, Y = 2 (b) X = 2, Y = 5
(c) X = 4, Y = 10 (d) X = 5, Y = 5
50. The oxidation state of nitrogen in NH 4
NO 3
is:
(a) -3 and +5 (b) +3 and +5
(c) +5 (d) +3
51. The oxidation number of nitrogen in NH 2
OH is:
(a) +1 (b) -1
(c) -3 (d) -2
52. Oxidation number of As atom in H 3
AsO 4
is:
(a) +5 (b) +6
(c) +4 (d) -3
53. Oxidation number of chlorine in HOCl is:
(a) Zero (b) -1
(c) +1 (d) +2
54. Nitrogen has fractional oxidation number in:
(a) N 2
H 4
(b) NH 4
(c) HN 3
(d) N 2
F 2
2–
55. Oxidation of thiosulphate(S 2
O 3
) ions by iodine gives
– 2–
(a) SO 3
(b) SO 4
2– 2–
(c) S 4
O 6
(d) S 2
O 8
56. The charge on cobalt in [Co(CN) 6
] 3– is:
(a) -6 (b) +3
(c) -3 (d) +6
57. The maximum oxidation state of osmium is :
(a) +7 (b) +8
(c) +10 (d) +6
58. In the compound KMnO 4
and K 2
Cr 2
O 7
, the highest
oxidation state is of the element:
(a) K
(b) Mn
(c) Cr
(d) O
59. The maximum oxidation state of chromium is:
(a) +6 (b) +4
(c) +8 (d) +7

PHYSICAL CHEMISTRY
1. b
2. a
3. c
4. d
5. c
6. b
7. c
8. c
9. a
10. a
11. a
12. c
13. b
14. b
15. a
16. a
17. a
18. c
19. a
20. c
21. a
22. c
23. c
24. c
25. d
26. d
27. b
28. d
29. a
30. a
A N S W E R S
31. a
32. c
33. d
34. c
35. a
36. b
37. c
38. a
39. d
40. b
41. a
42. a
43. b
44. d
45. a
46. a
47. a
48. b
49. b
50. a
51. b
52. a
53. c
54. c
55. c
56. b
57. b
58. b
59. a
by: SHAILENDRA KR.
1. Opp. Khuda Baksh Library, Ashok Rajpath, Patna - 4
2. House no. 5A/65, Opp. Mahual Kothi, Alpana Market, Patna
Page No.: 3