A 0.200 M NaOH solution was used to titrate a 18.25 mL HF solution. The endpoint was reached after 31.20 mL of titrant were added. Find the molar concentration of the original HF solution.
(31.20 / 18.25) * 0.200 M
so, how many moles in 31.2mL of 0,2M solution?
HF + NaOH = NaF + H2O
You will have that many moles of HF in 18.25mL. Molarity is moles/L
To find the molar concentration of the original HF solution, we can use the concept of stoichiometry and the volume and molarity of the NaOH solution used.
Step 1: Write the balanced chemical equation for the reaction between NaOH and HF:
NaOH + HF -> NaF + H2O
Step 2: Determine the moles of NaOH used in the titration:
Moles of NaOH = concentration of NaOH x volume of NaOH solution
= 0.200 M x 31.20 mL
= 6.24 mmol
Step 3: Use the stoichiometry of the balanced equation to find the moles of HF present in the titrated solution:
From the balanced equation, we can see that the molar ratio of NaOH to HF is 1:1. Therefore, the moles of HF present in the solution is also 6.24 mmol.
Step 4: Calculate the molar concentration of the original HF solution:
Molarity of HF solution = moles of HF / volume of HF solution
= 6.24 mmol / 18.25 mL
= 0.341 M (rounded to three decimal places)
Therefore, the molar concentration of the original HF solution is 0.341 M.
To find the molar concentration of the original HF solution, you can use the concept of stoichiometry and the equation for the neutralization reaction between NaOH and HF. The balanced equation for the reaction is:
NaOH + HF -> NaF + H2O
From this equation, you can see that the stoichiometric ratio between NaOH and HF is 1:1. This means that for every 1 mole of NaOH, there is 1 mole of HF.
First, let's determine the moles of NaOH used in the titration:
Moles of NaOH = Molarity of NaOH x Volume of NaOH (in liters)
Given that the molarity of NaOH is 0.200 M and the volume of NaOH added is 31.20 mL (which can be converted to liters by dividing by 1000):
Moles of NaOH = 0.200 M x 31.20 mL / 1000 mL/L = 0.00624 moles
Since the stoichiometry of the reaction is 1:1, the moles of HF present in the original solution are also equal to 0.00624 moles.
Now, let's calculate the molar concentration of the original HF solution:
Molarity of HF = Moles of HF / Volume of HF (in liters)
Given that the volume of HF used in the titration is 18.25 mL (which can be converted to liters by dividing by 1000):
Molarity of HF = 0.00624 moles / 18.25 mL / 1000 mL/L = 0.341 M
Therefore, the molar concentration of the original HF solution is 0.341 M.