n unknown amount of water is mixed with
350 mL of a 6 M solution of NaOH solution.
A 75 mL sample of the resulting solution is
titrated to neutrality with 52
.
5 mL of 6 M
HCl. Calculate the concentration of the di-
luted NaOH solution.
Answer in units of M
mols HCl = M x L = ?
mols NaOH = mols HCl (look at the coefficients in the balanced chemical equation).
M NaOH = mols NaOH/L NaOH
You know mols and L, solve for M. L for NaOH is 0.075 since you want M of the diluted solution.
To find the concentration of the diluted NaOH solution, we can use the concept of equivalence in titration. Equivalence is the point at which the moles of acid and base are equal.
First, let's calculate the number of moles of HCl used in the titration. We know the volume and concentration of the HCl solution.
Number of moles of HCl = volume × concentration
Number of moles of HCl = 52.5 mL × 6 M = 315 moles
Next, we need to determine the number of moles of NaOH that reacted with the HCl. Since NaOH and HCl react in a 1:1 ratio, the number of moles of NaOH is equal to the number of moles of HCl used.
Number of moles of NaOH = Number of moles of HCl = 315 moles
Now, let's calculate the volume of the diluted NaOH solution used in the titration. We know the volume of the NaOH solution and the volume of the water added.
Volume of the diluted NaOH solution = 350 mL + volume of water
Since the total volume of the solution is unknown and represented as n, we can write the equation:
Volume of the diluted NaOH solution = 350 mL + n mL
During the titration, 75 mL of the diluted NaOH solution was used. Therefore,
75 mL = 350 mL + n mL
n mL = 75 mL - 350 mL
n mL = -275 mL
Since we cannot have a negative volume, it means that there was too little water added, resulting in a negative volume. This implies that there was no water added, and the diluted NaOH solution is the same as the initial 350 mL of the 6 M NaOH solution.
Therefore, the concentration of the diluted NaOH solution is also 6 M (the same as the initial NaOH solution).
Hence, the concentration of the diluted NaOH solution is 6 M.