Question

In $GaCl_2$ the oxidation state of Ga is
A.+ 1 only
B.+2 only
C.+3 only
D.+1 and +3 only

Answer 1

During a chemical reaction the electrons are either gained or lost and thus the reaction gets completed. The two processes of loss and gain can occur individually as well as simultaneously together as well and thus the reaction proceeds as per the conditions.
The reaction in which the loss of electrons takes place is known as oxidation and the process in which the gain of electrons takes place is known as reduction. When these two processes occur together they are known as redox reaction.

Complete step by step answer:
There are certain rules regarding the oxidation states these are:
The oxidation state of the element in Free State is zero.
The oxidation state is equal to the net charge on the ion for a monatomic ion.
Hydrogen usually has an oxidation state of +1, oxygen has -2 oxidation state with some exceptions with the other compounds.
The algebraic sum of all the ions oxidation states in a compound must be equal to zero because the charge neutrality and stability is achieved in that way only.
The oxidation state of chlorine is (-1) and it is a halogen.
Let the oxidation state of Ga in $GaCl_2$ be x
The overall charge on the molecule will be 0
Therefore;
$= [x + ( - 1 \times 2)] = 0$
$= x - 2 = 0$
$x = + 2$

So, the correct answer is Option B.

Note: The applications of oxidation and reduction reactions are to know the number of electrons lost or gained during the chemical reaction processes, the redox reactions usually occur in most of the important processes in day to day life.