A 27.00 mL sample of an unknown H3PO4 solution is titrated with a 0.110 M NaOH solution. The equivalence point is reached when 25.78 mL of NaOH solution is added. What is the concentration of the unknown H3PO4 solution? The neutralization reaction is:
H3PO4(aq) + 3NaOH(aq) -> 3H2O(l) + Na3PO4(aq)
Grams
To find the concentration of the unknown H3PO4 solution, we can use the stoichiometry of the neutralization reaction, as well as the volumes and molarities of the solutions used.
First, let's determine the number of moles of NaOH used in the titration:
moles of NaOH = volume of NaOH solution (L) * molarity of NaOH solution (mol/L)
moles of NaOH = 25.78 mL * (1 L/1000 mL) * 0.110 mol/L
moles of NaOH = 0.00283 mol
According to the balanced equation, 1 mole of H3PO4 reacts with 3 moles of NaOH. Therefore, the number of moles of H3PO4 in the sample is:
moles of H3PO4 = (1/3) * moles of NaOH
moles of H3PO4 = (1/3) * 0.00283 mol
moles of H3PO4 = 0.000943 mol
Now, let's calculate the concentration of the unknown H3PO4 solution in terms of molarity:
concentration of H3PO4 = moles of H3PO4 / volume of H3PO4 solution (L)
concentration of H3PO4 = 0.000943 mol / (27.00 mL * (1 L/1000 mL))
concentration of H3PO4 = 0.035 mol/L
Therefore, the concentration of the unknown H3PO4 solution is 0.035 M.
To find the concentration of the unknown H3PO4 solution, you can use a stoichiometric calculation based on the balanced neutralization reaction. Here's how to approach the problem:
Step 1: Calculate the moles of NaOH used in the titration.
moles of NaOH = volume of NaOH solution (L) x molarity of NaOH solution (mol/L)
moles of NaOH = 0.02578 L x 0.110 mol/L
Step 2: Use the stoichiometry of the reaction to determine the moles of H3PO4.
From the balanced neutralization reaction, we can see that 1 mole of H3PO4 reacts with 3 moles of NaOH. Therefore, the moles of H3PO4 can be calculated as:
moles of H3PO4 = (moles of NaOH) x (1 mole of H3PO4 / 3 moles of NaOH)
Step 3: Calculate the concentration of the H3PO4 solution.
concentration of H3PO4 solution = moles of H3PO4 / volume of H3PO4 solution (L)
volume of H3PO4 solution = 27.00 mL = 0.02700 L
concentration of H3PO4 solution = (moles of H3PO4) / (volume of H3PO4 solution)
Based on the provided information, you can now perform these calculations to find the concentration of the unknown H3PO4 solution.
I'm glad you wrote the equation; otherwise I wouldn't have known to which of the three equivalence point you titrated.
mols NaOH = M x L = ?
mols H3PO4 = 1/3 that (look at the coefficients)
M H3PO4 = mols H3PO4/L H3PO4.