Final answer:
To find the grams of NaH₂PO₄needed, convert the volume of NaOH solution to moles using the molarity. Then, use the stoichiometry of the equation to determine the number of moles of NaH₂PO₄ needed. Finally, convert the moles of NaH₂PO₄ to grams using its molar mass.
Step-by-step explanation:
To determine the number of grams of NaH₂PO₄ needed to react with 36.29 mL of 0.250 M NaOH, we need to use the stoichiometry of the balanced equation.
The balanced equation is: NaH₂PO₄ (s) + 2 NaOH(aq) → Na₃PO4(aq) + 2 H₂O(1)
First, we convert the volume of NaOH solution to moles using the molarity:
Moles of NaOH = Volume (L) x Molarity = 36.29 mL x 0.250 mol/L = 0.00907 mol
Next, we use the stoichiometry of the equation to determine the number of moles of NaH₂PO₄ needed. From the balanced equation, we see that 1 mol of NaH2PO4 reacts with 2 mol of NaOH. Therefore, the number of moles of NaH₂PO₄ needed is twice the number of moles of NaOH:
Moles of NaH₂PO₄ needed = 2 x Moles of NaOH = 2 x 0.00907 mol = 0.0181 mol
Finally, we convert the moles of NaH₂PO₄ to grams using its molar mass:
Grams of NaH₂PO₄ = Moles x Molar mass = 0.0181 mol x 120.0 g/mol = 2.17 g