Rutgers University Standardizing a Sodium Hydroxide Solution Chemistry Lab Introductory Video: https://www.youtube.com/watch?v=5aGt__q39_4&feature=youtu.be
Rutgers University Standardizing a Sodium Hydroxide Solution Chemistry Lab Introductory Video: https://www.youtube.com/watch?v=5aGt__q39_4&feature=youtu.be
Lab Video https://www.youtube.com/watch?v=8UiuE7Xx5l8
Document attached below
Using the data provided, perform the calculations need to fill in the missing values on the report sheet. Do not use the data given in the videos.
Submit the lab as an attachment to this assignment (Word document only).
Professors Instructions^
Please let me know if you have any questions, thank you! Name:
CH 111 Introduction to Inorganic and Organic Chemistry
Exp. 350 Standardizing a Sodium Hydroxide Solution
INSTRUCTIONS
1.
2.
3.
4.
5.
Print out these instructions and the report sheet.
Read the Background/Introduction section of the lab manual and watch the intro video.
Watch the videos attached under the instructions.
Calculate the concentration of the NaOH solution using the calculations shown on the next page.
Submit both the report sheet and any supplementary questions as either a .doc or .pdf file and submit them as
an attached file under the lab assignment. No labs will be accepted by e-mail.
In this classic lab experiment, we are performing an acid-base titration. A titration is a lab technique often used to
determine the concentration of a solution, using another solution of known concentration. In an acid-base titration, one
of the reactants, in this case the acid HCl, is placed in a flask and titrated with the base NaOH, which is added to a buret.
A buret is a device used for the addition of a solution and measuring its volume. This is outlined in the video link that
goes along with this lab. In an acid-base titration, the two reactants are mixed until they have completely neutralized
each other. In order to know when we have reached the point of neutralization, we need something present in the
reaction to show us that the neutralization has occurred. That is why an indicator is added to the acid in the flask. An
indicator in this case would look one way in an acidic solution and look another way in basic solution. Phenolphthalein is
added to the acid in the flask before starting the titration. Phenolphthalein is clear in acidic solution and turns pink when
it is in a basic solution. The point when the indicator changes color is called the endpoint. Once the acid is neutralized,
the next tiny amount of NaOH that is added will turn the solution basic and thus the phenolphthalein will turn pink,
indicating that the titration is complete.
HCl (aq) + NaOH (aq)
NaCl (aq) + H2O (aq)
Report Sheet
Molarity of HCl: 0.1016 M
Trial
2
1
3
Volume of HCl (mL)
25.00
25.00
25.00
Final buret reading, mL
0.00
21.60
0.00
Initial buret reading, mL
21.60
44.30
20.20
Volume of NaOH (titrant)
Molarity of NaOH solution, mol L-1
Average molarity of NaOH solution, mol L-1
Supplementary Questions
1. Phenolphthalein is ___________ in acidic solutions, and ______________ in basic solutions.
2. What is the purpose of the phenolphthalein?
3. If a student added twice as much water to the HCl sample as specified in the lab, how would this affect the
answer?
Calculations
Volume NaOH used in titration = (Volume NaOH final) (Volume NaOH initial)
To find the Molarity of the NaOH:
Since the mole ratio of HCl and NaOH from the balanced equation is 1:1
the moles of HCl = moles of NaOH at the neutralization point.
Molarity = moles/Vol, so moles = Molarity x Volume
So, moles HCl = MHCl x VHCl and moles NaOH = MNaOH x VNaOH
Since the moles of HCl = moles of NaOH we can rewrite that as:
MHCl x VHCl = MNaOH x VNaOH
then rearranging the equation, we get:
Molarity NaOH =
???????? x ????????
??????????
Name:
CH 111 Introduction to Inorganic and Organic Chemistry
Exp. 350 Standardizing a Sodium Hydroxide Solution
INSTRUCTIONS
1. Print out these instructions and the report sheet.
2. Read the Background/Introduction section of the lab manual and watch the intro video.
3. Watch the videos attached under the instructions.
4. Calculate the concentration of the NaOH solution using the calculations shown on the next page.
5. Submit both the report sheet and any supplementary questions as either a .doc or .pdf file and submit them as
an attached file under the lab assignment. No labs will be accepted by e-mail.
In this classic lab experiment, we are performing an acid-base titration. A titration is a lab technique often used to
determine the concentration of a solution, using another solution of known concentration. In an acid-base titration, one
of the reactants, in this case the acid HCl, is placed in a flask and titrated with the base NaOH, which is added to a buret.
A buret is a device used for the addition of a solution and measuring its volume. This is outlined in the video link that
goes along with this lab. In an acid-base titration, the two reactants are mixed until they have completely neutralized
each other. In order to know when we have reached the point of neutralization, we need something present in the
reaction to show us that the neutralization has occurred. That is why an indicator is added to the acid in the flask. An
indicator in this case would look one way in an acidic solution and look another way in basic solution. Phenolphthalein is
added to the acid in the flask before starting the titration. Phenolphthalein is clear in acidic solution and turns pink when
it is in a basic solution. The point when the indicator changes color is called the endpoint. Once the acid is neutralized,
the next tiny amount of NaOH that is added will turn the solution basic and thus the phenolphthalein will turn pink,
indicating that the titration is complete.
HCl (aq) + NaOH (aq)
NaCl (aq) + H2O (aq)
Report Sheet
Molarity of HCl: 0.1016 M
Trial
1
2
3
Volume of HCl (mL)
25.00
25.00
25.00
Final buret reading, mL
0.00
21.60
0.00
Initial buret reading, mL
21.60
44.30
20.20
Volume of NaOH (titrant)
Molarity of NaOH solution, mol L-1
Average molarity of NaOH solution, mol L-1
Supplementary Questions
1. Phenolphthalein is ___________ in acidic solutions, and ______________ in basic solutions.
2. What is the purpose of the phenolphthalein?
3. If a student added twice as much water to the HCl sample as specified in the lab, how would this affect the
answer?
Calculations
Volume NaOH used in titration = (Volume NaOH final) (Volume NaOH initial)
To find the Molarity of the NaOH:
Since the mole ratio of HCl and NaOH from the balanced equation is 1:1
the moles of HCl = moles of NaOH at the neutralization point.
Molarity = moles/Vol, so moles = Molarity x Volume
So, moles HCl = MHCl x VHCl and moles NaOH = MNaOH x VNaOH
Since the moles of HCl = moles of NaOH we can rewrite that as:
MHCl x VHCl = MNaOH x VNaOH
then rearranging the equation, we get:
Molarity NaOH =
???????? x????????
??????????
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