When 10ml,2MNaOH solution is added to 20 ml of 1 M HCl solution :
NaOH+HCl→NaCl+H2O
Initial : MV =2×0.1MV=1×0.2
=0.2 mole =0.2 mole
Final 00
∴ Resulting solution becomes neutral.
Now when 10 mol of above solution is poured into a flask containing 2 mole HCl and made solution 100 ml will distilled water.
Molarity of HCl=1002×1000=20