The balanced chemical equation for the reaction between hydrochloric acid (HCI) and sodium hydroxide (NaOH) is:
HCI + NaOH -> NaCl + H2O
From the equation, we can see that 1 mole of HCI reacts with 1 mole of NaOH to produce 1 mole of NaCl and 1 mole of water.
First, let's calculate the number of moles of HCI in 250 mL of 0.25 M solution:
Molarity (M) = moles of solute / volume of solution (L)
0.25 M = moles of HCI / 0.25 L
moles of HCI = 0.25 L x 0.25 M = 0.0625 moles
Since 1 mole of NaOH reacts with 1 mole of HCI, we will need 0.0625 moles of NaOH to neutralize the HCI.
Now, let's calculate the volume of 0.9 M NaOH solution needed to provide 0.0625 moles of NaOH:
Molarity (M) = moles of solute / volume of solution (L)
0.9 M = 0.0625 moles of NaOH / volume of NaOH solution (L)
volume of NaOH solution (L) = 0.0625 moles / 0.9 M = 0.0694 L = 69.44 mL
Therefore, 69.44 mL of 0.9 M NaOH solution would be required to titrate 250 mL of 0.25 M HCI solution.