Q&A for How to Find Oxidation Numbers

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What is so2cl2 oxidation number of s?

Community Answer

We know Oxygen generally shows a oxidation number of -2. Therefore oxidation number of oxygen in SO2Cl2 is -2*2=-4. Also Cl has an oxidation number of -1. Therefore oxidation number of Cl2 in SO2Cl2 is -1*2=-2. Let the oxidation number of S be X. Now the overall charge is 0. So -4+(-2)+X=0.Therefore X=6. Therefore oxidation number of S in SO2Cl2 is +6.

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Does electronegativity have an affect on the oxidation state?

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Yes. In normal cases, O has a oxidation number of -2. But in OF2 , F is more electronegative than O. So, in OF2, oxidation numbers of O and F are +2 and -1, respectively.

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What is the relation between the oxidation number and valency in case of s-block metals?

Community Answer

Oxidation is the ionic number of an element, while valency is the number that shows the relationship of chemical properties of elements in the same group, so the oxidation number of an element is also the number of valence electrons.

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Can you determine the oxidation number based on valence electrons?

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Yes. In the case of a molecule, you have to see how many electrons each element needs to fill its shell. For example, NaCl. Sodium has one valence electron that it wants to give away to drop down to its complete the 8 electron shell. Chlorine wants to get one electron to complete its shell (since it has 7 Ve- and needs one to get the complete 8.) So we know that sodium will be +1 (it gives an electron-, therefore has 1 more proton+ than electrons-). Chlorine will be -1 because it takes an electron (and has one more electron- than protons+).

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What is the oxidation number of CaCo3?

Community Answer

Oxidation number of Ca is +2 Oxidation number of O is (3*-2= -6) Overall charge is zero. So oxidation number of C is +4.

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What is the formula of finding an oxidation number?

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There is no formula -- it's a technique. You just need to find the unknown value. It's the same idea as solving equations with one variable.

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How do I determine reduction and oxidized compounds?

Community Answer

A decrease in oxidation number means reduction, and an increase means oxidation.

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Question

Normally, O2 when it combines with other element it will acquire the -2 oxidation state but in the case of H2O2, oxygen is having an oxidation number of -1. Why is this different?

Community Answer

Because the overall charge of the compound is zero. And we know that the oxidation number of H is +1. So, 2*(+1) + 2x = 0 As in 2 multiplied by the oxidation number of H, that is +1 added to 2 into X, (X stands for oxygen) equals to zero. When you solve that you get -1 as an answer for X, the oxidation number of oxygen for this compound.

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What is the oxidation number for k2Cr2O7?

Community Answer

ON of Oxygen is -2, the ON of Potassium is+1. Let us assume ON of Cr is x. So, 2(+2)+ 2x + 7(-2) = 0. Here 0 is the net charge on the compound. You get 4+2x-14=0, 2x=12, x=+6.

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What will be the oxidation number of CUSO4?

Community Answer

In this case we know the sulfate polyatomic ion (SO4) has a charge of 2-. Therefore, Cu has a charge of 2+. Sulfur's oxidation number is +6 in this case, because we know SO4 has a total of -2, and we know the the 4 oxygens contribute -8 (4 x -2).

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Question

What is the difference between oxidation number and oxidation state?

Community Answer

When you're determining the oxidation state, the electronegativity of the atoms in a bond is not taken into account, which isn't the case when determining oxidation number.

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What is oxidation state of N in N3H?

Community Answer

Let the oxidation number of nitrogen be x. The oxidation number of hydrogen is +1. Therefore, 3x + 1 = 0. 3x = -1. x = -1/3.

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Question

How can I know the oxidation state of a single element?

Community Answer

The oxidation state of an element in its uncombined state is the charge on it -- so, the charge on the element tells you its oxidation state. For example, the oxidation number of O in its uncombined state is zero.

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Question

In the following chemical reactions, state whether red-x reaction takes place, and name the elements reduced or oxidized: 2h2 + O2 = 2H2?

Kalpna Kehal

Community Answer

In this reaction product is water, H2O. O.S. of H changes from 0 to +1, hence it is oxidized, while o.s. of O changes from 0 to -2, indicating its reduction.

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What is the oxidation number of nitrogen in HNC?

Community Answer

In HNC, the oxidation number of hydrogen is +1, and the oxidation number of carbon is +2. Let the oxidation number of nitrogen be x. Then (+1) + x + (+2) = 0. x+3=0. x = -3.

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What if the answer is a fraction like that of Na2S4O6?

Community Answer

The answer can be a fraction. For example, in O2-, the oxidation state is -0.5 per oxygen atom.This just theoretical, as practically there is nothing that has a fractional charge (there are no fractional electrons).

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How can I determine the number of peroxide bonds in (CrO5)?

Community Answer

The prefix 'per' means 2. If you want to find O bonds, look on the periodic table. Try drawing a diagram to help.

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Question

What is the oxidation number of KMnO4?

Community Answer

K being an alkali metal has an oxidation number of 1. O generally has -2 except in the case of peroxides and superoxides. Here, O has 4 moles, so (4*-2= -8). Let oxidation number of Mn be 'x'. 1 + x +(-8) = 0. x - 7 = 0. x = 7. Hence Mn has an oxidation number of 7.

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Question

How do I find the oxidation state of FeCl2?

Community Answer

The oxidation number of Cl is -1. There are 2 atoms of Cl in the compound. So the charge is -1 * 2 = -2, and the ON of Fe is +3; 3 * -2 + 3 * 2 = -6 + 6 = 0.

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What is the oxidation number of Fe(NO3)3?

Community Answer

We know that the oxidation number of NO3 is -1. We will multiply it by 3, that is (-1)3 =-3. The overall charge must be zero, so Fe will have an oxidation number of +3 in this case.

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How do I find the oxidation number of boron?

Community Answer

Boron has an atomic number of 5 draw the orbital shell. Notice that the litter shell gives a 3, since valence shell electron is equal to the oxidation number so +3 is usually the answer (with some exceptions).

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