# Process Of Oxidation Numbers Quiz

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Soffe1399
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Oxidation states simplify the whole process of working out what is being oxidized and what is being reduced in redox reactions. See if you can guess the following oxidation numbers.

• 1.

### What is the oxidation state of sulfur in S2O3?

• A.

+2

• B.

-2

• C.

+3

• D.

-3

C. +3
Explanation
The oxidation state of sulfur in S2O3 is +3. This is because each oxygen atom in the compound has an oxidation state of -2, and the overall charge of the compound is -2. Since there are three oxygen atoms, the total oxidation state contributed by oxygen is -6. In order to balance the overall charge of -2, the oxidation state of sulfur must be +3.

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• 2.

### What is the oxidation state of oxygen in S2O3?

• A.

+2

• B.

-2

• C.

+3

• D.

-3

B. -2
Explanation
The oxidation state of oxygen in S2O3 is -2. This is because oxygen is more electronegative than sulfur, and in most compounds, oxygen has an oxidation state of -2. Since there are three oxygen atoms in S2O3, the total oxidation state contribution from oxygen is -6. The overall oxidation state of the compound is 0, so the oxidation state of sulfur must be +6 to balance out the -6 contribution from oxygen. Therefore, each oxygen atom in S2O3 has an oxidation state of -2.

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• 3.

### What is the oxidation state of phosphorus in P2O5?

• A.

+5

• B.

-5

• C.

+2

• D.

-2

A. +5
Explanation
The oxidation state of phosphorus in P2O5 is -2. This is because oxygen is typically assigned an oxidation state of 5.

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• 4.

### What is the oxidation state of oxygen in P2O5?

• A.

+2

• B.

-2

• C.

+5

• D.

-5

A. +2
Explanation
The oxidation state of oxygen in P2O5 is +2. In this compound, phosphorus has an oxidation state of +5, and since there are two oxygen atoms for every phosphorus atom, the total oxidation state contributed by oxygen is -10. Since the overall charge of P2O5 is 0, the oxidation state of oxygen must be +2 to balance out the -10 contributed by phosphorus.

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• 5.

### What is the oxidation state of chromium in Na2Cr2O7?

• A.

+2

• B.

-2

• C.

+6

• D.

+7

C. +6
Explanation
The oxidation state of an element refers to the charge it would have if all its bonds were ionic. In Na2Cr2O7, sodium (Na) has an oxidation state of +1 since it belongs to Group 1 of the periodic table. Oxygen (O) usually has an oxidation state of -2. By assigning x to the oxidation state of chromium (Cr), we can set up the equation: 2(+1) + 2x + 7(-2) = 0. Solving this equation gives us x = +6, indicating that the oxidation state of chromium in Na2Cr2O7 is +6.

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• 6.

### What is the oxidation state of oxygen in Na2Cr2O7?

• A.

+2

• B.

-2

• C.

+7

• D.

-7

B. -2
Explanation
The oxidation state of oxygen in Na2Cr2O7 is -2. This is because the overall charge of the compound is 0, and since there are two oxygen atoms, the total charge contributed by them is -4. Therefore, each oxygen atom must have an oxidation state of -2 in order to balance out the positive charges of sodium and chromium.

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• 7.

### What is the oxidation state of aluminum in Al2(SO4)3?

• A.

+2

• B.

-2

• C.

+3

• D.

-3

C. +3
Explanation
In the compound Al2(SO4)3, the sulfate ion (SO4) has a charge of -2. Since there are three sulfate ions, the total charge contributed by them is -6. The overall charge of the compound must be neutral, so the two aluminum ions (Al) must contribute a total charge of +6 to balance out the negative charge. Since there are two aluminum ions, each aluminum ion must have an oxidation state of +3 to give a total charge of +6. Therefore, the oxidation state of aluminum in Al2(SO4)3 is +3.

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• 8.

### What is the oxidation state of sodium in Na2O2?

• A.

+1

• B.

-1

• C.

+2

• D.

-2

A. +1
Explanation
In Na2O2, the oxidation state of oxygen is -1. Since the overall charge of the compound is 0, the oxidation state of sodium can be calculated as follows: 2(+1) + 2(-1) = 0. Therefore, the oxidation state of sodium in Na2O2 is +1.

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• Current Version
• Jan 07, 2024
Quiz Edited by
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• Mar 27, 2016
Quiz Created by
Soffe1399

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