Answer : The correct option is, (D)
Explanation :
Option A reaction : 
It is a combustion reaction. A reaction in which a hydrocarbon react with the oxygen to give product as carbon dioxide and water.
Option B reaction : 
It is a combination reaction. A reaction in which the two or more reactants react to give a product.
Option C reaction : 
It is a decomposition reaction. A reaction in which a reactant decomposes to form two or more products.
Option D reaction : 
It is a single displacement reaction. It is a reaction in which the more reactive element displace the less reactive element. In this reaction, most reactive element chlorine displaces the less reactive element bromine.
Hence, the correct option is, (D)
Oxygen gains two electrons when it bonds to form a complete outer shell and magnesium loses two electrons when bonding to gain its full outer shell.
As electrons are negative, the oxygen (which gains electrons) will become negative and the magnesium (which loses electrons) will become positive.
The negative and positive ions will then attract to one another due to the magnetic pull of the positive and negative.
Answer:
HOFO = (0, 0, +1, -1)
Explanation:
The formal charge (FC) can be calculated using the following equation:

<u>Where:</u>
V: are the valence electrons
N: are the nonbonding electrons
B: are the bonding electrons
The arrange of the atoms in the oxyacid is:
H - O₁ - F - O₂
Hence, the formal charge (FC) on each of the atoms is:
H: FC = 1 - 0 - 1/2*(2) = 0
O₁: FC = 6 - 4 - 1/2*(4) = 0
F: FC = 7 - 4 - 1/2*(4) = +1
O₂: FC = 6 - 6 - 1/2*(2) = -1
We can see that the negative charge is in the oxygen instead of the most electronegative element, which is the F. This oxyacid is atypical.
I hope it helps you!
I think it’s A, because all of these are related to fossil fuel somehow.