Identify the missing coefficient in the balanced equation and classify the type of reaction.
Cl2O3 + H20- HCIO3

The balanced equation with the missing coefficient is given as

                           

This type of reaction is called as Double Displacement reaction.

Explanation:

The given equation is Cl2O3 + H20 ---> HCIO3 + H2. For the reaction to be balanced, the number of atoms of each element must be equal on both sides of the reaction arrow. On the left side, we have

                              Cl: 2

                              O : 3 + 1 = 4

                              H: 2

And on the right side,

                              H : 1 + 2 = 3

                              Cl: 1

                              O : 3

You will notice that there is a shortage of Chlorine and Oxygen atoms on the right side and the Hydrogen atom is not correctly balanced. To make it a balanced ratio, add 3 to the H2O on the left side, 2 to the HClO3, and 2 to the H2.

Now the balanced equation becomes,

                 

This type of reaction is called a Double Displacement reaction in which an acid and a base react in aqueous solution to form a salt and (usually liquid) water.