Chemistry Homework Solutions
Problem
#52868

Experimental analysis

The attached document gives the procedure and results for a hypothetical experiment.  Four questions follow the information provided.  Please answer those four questions.

(See attached file for full problem description)

---
A certain experimental procedure is as follows:
1.  You react an unknown alcohol with acetic anhydride in a condenser.  (The temperature of the alcohol solution drops with the addition of acetic anhydride).
2.  Sulfuric acid is then added with the alcohol and the acetic anhydride in the condenser.  (This causes an exothermic reaction).
3.  After the temperature of the above reaction has dropped back down to room temperature, the mixture is transferred to a separatory funnel, using a 50 mL diethyl ether rinse to aid the transfer
4.  The ether solution is washed with ice cold 5% NaOH.  
5.  After the last extraction, the pH of the organic solution is checked to be sure it is basic.  The organic portion is then washed with saturated sodium chloride solution, dried with sodium sulfate, and filtered into a 100 mL roundbottom flask.
6.  The ether and the product are fractionally distilled.

It turns out that product that is fractionally distilled (along with the ether) in the end is isoamyl acetate (also called isopentyl acetate).  This implies that the reaction between the unknown alcohol and the acetic anhydride produced isoamyl acetate.  

Questions:

1.  This shows stepwise how an ester is formed from the reaction of an alcohol and acetic anhydride. Substitute the alkyl group you have determined for R, and draw in curved arrows to show the movement of electrons in the reactions.

2.What is the structure of your unknown alcohol, and how did you arrive at this conclusion?

3.How would not adding sulfuric acid to the reaction mixture affect your results?  

4.  What is the theoretical % yield of your ester?
---

Attached file(s):
Attachments
fake experiment.doc  View File

Attachment Content Summary (Note: view attachment at the above link before purchasing. Actual attachment content may vary slightly from that shown below.)

fake experiment.doc
A certain experimental procedure is as follows:

1. You react an unknown alcohol with acetic anhydride in a condenser.
(The temperature of the alcohol solution drops with the addition of
acetic anhydride).

2. Sulfuric acid is then added with the alcohol and the acetic
anhydride in the condenser. (This causes an exothermic reaction).

3. After the temperature of the above reaction has dropped back down to
room temperature, the mixture is transferred to a separatory funnel,
using a 50 mL diethyl ether rinse to aid the transfer

4. The ether solution is washed with ice cold 5% NaOH.

5. After the last extraction, the pH of the organic solution is checked
to be sure it is basic. The organic portion is then washed with
saturated sodium chloride solution, dried with sodium sulfate, and
filtered into a 100 mL roundbottom flask.

6. The ether and the product are fractionally distilled.

It turns out that product that is fractionally distilled (along with the
ether) in the end is isoamyl acetate (also called isopentyl acetate).
This implies that the reaction between the unknown alcohol and the
acetic anhydride produced isoamyl acetate.

Questions:



1. This shows stepwise how an ester is formed from the reaction of an
alcohol and acetic anhydride. Substitute the alkyl group you have
determined for R, and draw in curved arrows to show the movement of
electrons in the reactions.

2.What is the structure of your unknown alcohol, and how did you arrive
at this conclusion?

3.How would not adding sulfuric acid to the reaction mixture affect your
results?

4. What is the theoretical % yield of your ester?
Solution
What is this?
By OTA - Overall OTA Rating
Ibrahim Ojikutu, PGD - 4.3/5
Purchase Cost Now
$2.19 CAD (was ~$19.95)
Included in Download
  • Plain text response
  • Attached file(s):
    • Isopentyl alcohol.jpg
    • Isopentyl alcohol 1.jpg
$2.19 Instant Download
Add to Cart
Why you can trust BrainMass.com
  • Your Information is Secure
  • Best Online Academic Help Service
  • Students find real academic Success
Related Solutions
  • A hypothetical compound has a formula of X2YZ3. - A hypothetical compound has a formula of X2YZ3. If the atomic masses of X, Y, and Z are 41.2, 57.7 and 63.9 respectively, calculate the % by mass of the compound. If the molecular formula is actuall ...
  • Molecular formula of a compound - 1. What is the molecular formula of a compound? See attached file for full problem description.
  • Titration - Second method for determining the Ka of acetic acid by titration with NaOH. I would like to see the details of the calculations. For my lab experiment I have the following data: Titration#1 4 ...
  • The Nernst Equation - (See attached file for full problem description) --- The Nernst equation is the most important equation in electrochemistry. It is defined as follows: Where is the standard reduction poten ...
  • Titration - Titration of Borax w/HCl 1. Would the experimental values of Ksp, ∆H◦, ∆S◦, ∆G◦ be affected if the samples titrated contained large amounts of solid borax? If ...
Browse