The reaction for burning of charcoal or complete combustion is as follows:

From the above balanced reaction, 1 mole of carbon releases 1 mole of
gas.
Converting mass of charcoal into moles as follows:

Molar mass of pure carbon is 12 g/mol thus,

The same moles of
is released. Converting these moles into mass as follows:
m=n×M
Molar mass of
is 44 g/mol thus,

Converting mass into kg,

Thus, total mass of gas released is 5.5 kg.
Answer: C)Anion, it would gain 2 electrons to satisfy the octet rule.
Explanation:
Electronic configuration represents the total number of electrons that a neutral element contains. We add all the superscripts to know the number of electrons in an atom.
The electrons are filled according to Afbau's rule in order of increasing energies and thus the electronic configuration of oxygen with 8 electrons is

The cation is formed by loss of electrons and anions are formed by gain of electrons.
In order to complete its octet and get stable, it gains 2 electrons and thus would form an anion.

I don’t know if I am right but I think it is symbol for the first one and the second one is formula.
Answer: Rate law is, R= 6.02[A]¹[B]²
Explanation in attached image