Which among the following is not a balanced equation ?

Explanation

(i) The number of atoms of the elements in the reactants is same as the number of atoms of those elements in the products. Such an equation is called a 'balanced equation'.
(ii) In any reaction, the total mass of each of the each of the respectivel elements in the reactants is same as the total mass of each of the respective elements in the products.
(iii) This is in accordance with the law of conservation of mass.
e.g. `SO_(2)+ 2H_(2)S to 3S+2H_(2)O`
`{:("On reactant side", "On product side"),("No. of atoms of", "No. of atoms of"),("Sulphur(S)=3","Sulphur (S) =3"),("No. of atoms of","No. of atoms of"),("Oxygen (O)=2","Oxygen (O)=2"),("No. of atoms of","No. of atoms of"),("hydrogen (H) =4","hydrogen (H) =4"):}`
`therefore` The given equation is balanced.