Explanation:
A balanced equation is defined as the one that has equal number of atoms of all the elements present on both reactant and product side.
(a)
Number of atoms on reactant side are as follows.
Mg = 1
O = 6
H = 3
Cl = 1
Number of atoms on product side are as follows.
Mg = 1
O = 9
H = 2
Cl = 2
So, to balance this equation we multiply by 2 on reactant side and multiply
by 2 on product side.
Therefore, the balanced reaction equation is as follows.
(b)
Number of atoms on reactant side are as follows.
S = 1
O = 4
H = 2
Number of atoms on product side are as follows.
S = 1
O = 4
H = 2
Therefore, this equation is balanced as it has same number of atoms on both reactant and product side.
(c)
Number of atoms on reactant side are as follows.
Sr = 1
O = 1
H = 2
S = 1
O = 4
Number of atoms on product side are as follows.
Sr = 1
O = 1
H = 2
S = 1
O = 4
Therefore, this equation is balanced.