Question

How much of the excess reactant do you expect to be left over if the reaction goes to completion?

Answer 1

Whenever any excess amount of reactant is present in the reaction mixture , the excess of it remains after the reaction goes to completion .

For example :

A + B ---> C + D

Suppose 1 mole of A and 2 moles of B are present in the reaction mixture.

Now we can clearly see that equimolar concentrations of both the reactants are required , so 1 mole of A will require 1 mole of B to produce 1 mole of each of the products C ,and D.

Since only one mole of B is utilised , it remains after the reaction is completed.

The number of moles of B left = 2 - 1 = 1 mole.