To solve this problem, we can use the balanced chemical equation between HCl and Na2CO3:
2 HCl + Na2CO3 -> 2 NaCl + H2O + CO2
Based on the equation, we can see that 2 moles of HCl reacts with 1 mole of Na2CO3.
First, we need to calculate the number of moles of Na2CO3 using its concentration and volume:
moles of Na2CO3 = concentration * volume
= 0.200 M * 0.750 L
= 0.150 moles
Since the stoichiometry between HCl and Na2CO3 is 2:1, we need twice as many moles of HCl as Na2CO3 to completely react.
moles of HCl = 2 * moles of Na2CO3
= 2 * 0.150 moles
= 0.300 moles
Finally, we can use the concentration of HCl to find the volume needed to react completely:
volume of HCl = moles of HCl / concentration
= 0.300 moles / 2.25 M
= 0.133 L
Therefore, a volume of 0.133 liters of 2.25 M HCl is needed to react completely with 0.750 liters of 0.200 M Na2CO3.