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.
contain 
bromine atoms![PBr_{3}[/tex contains one P atom and three Br atomsSo 1 mol of [tex]PBr_{3}[/tex contains 3 moles of Br.We know that 1 mol = [tex]6.023\times 10^{23}](/tpl/images/0092/3997/86244.png)
molecules
atoms of Br in 1 mol of 
moles of 
