Determine the oxidation number of chromium in potassium dichromate, K2Cr2O7.

2+x−14=0

−12+x=0

x=12

Explanation:

assium exhibits an oxidation state of +1, oxygen exhibits an oxidation state of -2

So, the total charge of potassium ions is +1(2)=+2, while oxygen ions is −2(7)=−14.

Let x be the oxidation number of two chromiums.

Hence we can write the equation as

2+x−14=0

−12+x=0

x=12

So, two chromium atoms have an oxidation number of +12.

So one chromium atom will have an oxidation number of +12 /2=+6.

So oxidation number of Cr in K2Cr2O7 is +6.

answer: - 3.) the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

solution: - as per the rules, oxidation number of oxygen in its compounds is -2. the sum of oxidation numbers of all the elements of a molecule or compound is zero.

also, the oxidation number in elemental form is zero.

in no, the oxidation number of o is -2 so the oxidation number of n is +2 so that the sum is zero.

similarly, the oxidation number of c in co is +2 and o is -2.

on product side the oxidation number of n is 0 as it is in the elemental form() .

oxidation number of c in carbon dioxide is +4 as there are two oxygen in it and we know that each oxygen is -2.

so, oxidation number of n is changing from +2 to 0 and the oxidation number of c is changing from +2 to +4.

since nitrogen is reduced and hence no is acting as an oxidizing agent. carbon is oxidized and so co is acting as a reducing agent.

so, the right choice is number 3.)the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

it is stable as it is in group 0 which have full outer shells of electrons