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Worksheets

Redox Reactions

Total questions: 20

Worksheet time: 29mins

Name
Class
Date
1.
What element is being Oxidized?
a)
N
b)
H
c)
O
d)
S
2.
Is calcium oxidized or reduced in the following reaction? 
2 CaO--> 2 Ca + O2
a)
Oxidized
b)
Reduced
3.
Which of the following half reactions correctly represents a reduction half reaction?
a)
Fe →Fe2+ + 2e-
b)
Pb4+ + 2e- →Pb2+
c)
2O-2 →O2 + 4e-
d)
Fe + 3e- →Fe3+
4.

What is the oxidation number of chlorine in HClO?

a)

0

b)

-1

c)

+1

d)

+5

5.

Reduction is the ___________ of electrons.

a)

loss

b)

gain

c)

sharing

d)

transfer

6.

What is the oxidation number of iodine in KIO3?

a)

0

b)

-1

c)

+5

d)

+1

7.

Determine the oxidation number of chromate in CrO42-.

a)

+6

b)

0

c)

+2

d)

+3

8.

Which of the following represents oxidation?

a)

C → CH4

b)

Fe3+ → Fe2+

c)

Cl2 → 2Cl-

d)

Zn → ZnO

9.

In the reaction Zn + 2HCl --> ZnCl2 + H2

which element, if any, is oxidized?

a)

Zinc

b)

Hydrogen

c)

Chlorine

d)

None

10.
What is oxidation number of H in CaH2?
a)
+1
b)
-1
c)
0
d)
+2
11.

What is the oxidation number of C in SrCO3?

a)

-4

b)

+2

c)

-6

d)

+4

12.

Substance that oxidizes another substance by accepting its electrons.

a)

reducing agent

b)

oxidation number

c)

disproportionation

d)

oxidizing agent

13.

Which equation represents a redox reaction?

a)

NaOH + HNO3 → NaNO3 +H2O

b)

2AgNO3 + Zn → Zn(NO3)2 + 2Ag

c)

2NaCl + Pb(NO3)2 → PbCl2 + 2NaNO3

d)

CaCO3 + 2HCl → CaCl2 + H2O + CO2

14.

What is the oxidation number of X in XO4-?

a)

+4

b)

+5

c)

+7

d)

+8

15.

The following chemical equation represents the extraction of silicon from quartz using coke.

SiO2 + C → Si + CO2

What is the change in oxidation number of silicon?

a)

+2 to 0

b)

+4 to 0

c)

0 to +2

d)

0 to +4

16.

Consider the following reaction.

NO3 (aq) + Cu (s) → NO (g) + Cu2+ (aq)

Which statement is correct?

a)

Cu (s) is the reducing agent because it loses electrons.

b)

Cu (s) is the reducing agent because it gains electrons.

c)

Cu (s) is the oxidizing agent because it loses electrons.

d)

Cu (s) is the oxidizing agent because it gains electrons.

17.

What is the oxidation number of Mn in the following: MnO4-, MnO42- and MnO2?

a)

+4, +6, +7

b)

+7, +6, +4

c)

+2, +4, +7

d)

+5, +3, +4

18.

What is the oxidizing agent in the following reaction?

Zn (s) + Cu2+ (aq) Zn2+ (aq) + Cu (s)

a)

Zn (s)

b)

Cu2+ (aq)

c)

Zn2+ (aq)

d)

Cu (s)

19.

Al (s) + FeSO4 (aq) → Al2(SO4)3 (aq) + Fe (s)

Which statements are true about this reaction?

I. Al (s) reduces Fe2+ (aq)

II. Al (s) is the oxidizing agent.

III. FeSO4 is the reducing agent.

a)

I and II only

b)

I and III only

c)

II and III only

d)

I, II and III

20.

Which statement is NOT true when the following redox reaction is balanced?

Cu (s) + NO3- (aq) → NO (g) + Cu2+ (aq) [acidic]

a)

There are 8H+ (aq) in the reactant side.

b)

There are 2H2O (l) in the product side.

c)

There are 4H2O (l) in the product side.

d)

There are 6e- in both half-equations.