Answer:
Conditioning two or three times will insure that the concentration of titrant is not changed by a stray drop of water.
Explanation:
"Check the tip of the buret for an air bubble. To remove an air bubble, whack the side of the buret tip while solution is flowing".
If the refrigerator has no room to cool the meat that you've just cooked, then you should clear it with other stuff or food that has not been consumed for days. There might be some goods that are not good for consumption anymore even though it has been placed in the ref for a couple of days. Hope this answers your question.
Mole ratio for the reaction is 1:1
no of moles in NaOH that reacted= 1*21.17/1000=0.02117mols
molarity of HCl=0.02117*10/1000
=2.117M