Noah is conducting a science experiment and needs to analyze iron and sulfur. Which of the following will he compare to determin
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The question is incomplete, here is the complete question:
A chemist titrates 110.0 mL of a 0.2412 M hypochlorous acid (HCIO) solution with 0.0613 M NaOH solution at 25°C. Calculate the pH at equivalence. The pKa of hypochlorous acid is 7.50. Round your answer to 2 decimal places
<u>Answer:</u> The pH of the solution is 10.09
<u>Explanation:</u>
To calculate the volume of base, we use the equation given by neutralization reaction:
where,
are the n-factor, molarity and volume of acid which is
are the n-factor, molarity and volume of base which is NaOH.
We are given:
Putting values in above equation, we get:
At equivalence, the number of moles of acid is equal to the number of moles of base. Also, the moles of salt which is NaClO will also be the same.
To calculate the number of moles for given molarity, we use the equation:
.....(1)
- <u>For HClO:</u>
Molarity of HClO solution = 0.2412 M
Volume of solution = 110.0 mL
Putting values in equation 1, we get:
- <u>For NaClO:</u>
Moles of NaClO = 0.026532 moles
Volume of solution = [432.8 + 110] mL = 542.8 mL
Putting values in above equation, we get:
To calculate the pH of the solution, we use the equation:
where,
= negative logarithm of weak acid which is hypochlorous acid = 7.50
C = concentration of the salt = 0.0489 M
Putting values in above equation, we get:
Hence, the pH of the solution is 10.09
Answer : The resulting concentrations of CV and NaOH are 0.0027 M and 0.025 M respectively.
Explanation :
Step 1 : Find moles of crystal violet and NaOH.
The molarity formula is
Molarity of crystal violet =
The volume of crystal violet solution is 18 mL which is 0.018 L.
Moles of crystal violet =
Moles of crystal violet = 5.4 x 10⁻⁵
Moles of NaOH =
Moles of NaOH = 5.00 x 10⁻⁴
Step 2 : Find total volume of the solution
The total volume of the solution after mixing NaOH and crystal violet is
0.018 L + 0.00200 = 0.020 L
Step 3 : Use molarity formula to find final concentrations
Molarity of crystal violet =
Final concentration of CV = 0.0027 M
Molarity of NaOH=
NaOH is a strong base and dissociates completely as follows.
The mole ratio of NaOH and OH⁻ is 1:1 . Therefore the concentration of OH⁻ is same as that of NaOH.
Concentration of OH⁻ = 0.025 M