**Please explain every step, step by step and make clear explanations along the way**

Consider the titration of a 20.0 mL of a .100 M aqueous solution of a hydrochloric acid (HCl: a strong monoprotic acid) with a .120 M aqueous solution of sodium hydroxide (NaOH: a strong base). Calculate the pH of the solution at each of the following points:
Before any base has been added to the solution
Halfway to the equivalence point
At the equivalence point
After the addition of 10.0 mL of base past the equivalence point.
Sketch the form of the titration curve with important points