We use the calculation to determine the Normality of the HCl.
A “standardization titration” is just a comparison of the molarity of the standard to the unknown (HCl in this case) by means of the volumes.
A “Normal” solution is often used for acid-base titrations because it accounts for the possible differences in reactive components. For example, a “diprotic” acid (like sulfuric acid) with a Molarity of 1.0 would have a Normality of 2.0 because it can react with 2 “equivalent” moles of a base.
In this example we have a basic compound with the same characteristic. If we used molarities directly, we would need to correct for the “extra” reactivity in the borax compared to the hydrochloric acid.
Using Normalities we can calculate the acid-base equivalence directly, and correct for molarities later, if desired.
SO, we titrate the HCl with the standard solution of 0.01N borax. The calculation is:
Now you have a calibrated HCl solution.