EDIT: I did the titration. I made use of 500ml of my stock solution HCl, and titrated towards my stock solution of NaOH. HCl is 0.001M and NaOH is 5M.Alternatively, When you have an alkali-resistant stopper, You can utilize it to the flask and shake. Don't shake also vigourously. There will be stress buildup. Make sure to take out the stopper after