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Experimental procedure

CAUTION WEAR EYE PROTECTION!

 

CAUTION - Concentrated sulfuric acid will burn and stain the skin as well as damage clothing. In case of skin or clothing contact, wash the area immediately with large amounts of water.

Synthesis of esters

  • Place approximately 2 g (or 2 mL if the substance is a liquid) of the organic acid and 2 mL of the alcohol in a large test tube.
  • Add 5 - 7 drops of concentrated (18 M) sulfuric acid, mix the solution well with a glass stirring rod and then place the test tube in a hot water bath (largest beaker in your drawer) (~ 80°C) for 5 - 10 minutes.
  • Remove the test tube from the hot water bath and cautiously pour the mixture into about 15 mL of saturated sodium bicarbonate contained in a small beaker. The sodium bicarbonate will destroy any unreacted acid.
  • Observe the aroma produced from each of the following esterification reactions. Write the structure of the esters produced, and the balanced equations for the esterification and the acid/sodium bicarbonate reactions:

 

Complete the following reactions using the procedure above and record your observations.

 

 (1) C 7 H 6 O 3 + CH 3 OH size 12{C rSub { size 8{7} } H rSub { size 8{6} } O rSub { size 8{3} } + ital "CH" rSub { size 8{3} } ital "OH" rightarrow } {}

 salicylic acid + methyl alcohol

 (2) CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 OH + CH 3 COOH size 12{ ital "CH" rSub { size 8{3} } ital "CH" rSub { size 8{2} } ital "CH""" lSub { size 8{2} } ital "CH" rSub { size 8{2} } ital "CH" rSub { size 8{2} } ital "CH" rSub { size 8{2} } ital "CH" rSub { size 8{2} } ital "CH" rSub { size 8{2} } ital "OH"+ ital "CH" rSub { size 8{3} } ital "COOH" rightarrow } {}

1 - octanol + glacial acetic acid

 (3) CH 3 CH 2 CH 2 CH 2 CH 2 OH + CH 3 COOH size 12{ ital "CH" rSub { size 8{3} } ital "CH" rSub { size 8{2} } ital "CH""" lSub { size 8{2} } ital "CH" rSub { size 8{2} } ital "CH" rSub { size 8{2} } ital "OH"+ ital "CH" rSub { size 8{3} } ital "COOH" rightarrow } {}

 amyl alcohol + glacial acetic acid

(4) C 2 H 5 OH + CH 3 COOH size 12{C rSub { size 8{2} } H"" lSub { size 8{5} } ital "OH"+ ital "CH" rSub { size 8{3} } ital "COOH" rightarrow } {}

ethanol + acetic acid

 

Oxidation of an alcohol with acidified potassium dichromate(vi) solution

  • Add 10 drops of dilute sulfuric acid (6M) and 5 drops of potassium dichromate(VI) solution (0.01M) to 5 drops of ethanol. The oxidising agent is added slowly to the alcohol so that the temperature is kept below that of the alcohol and above that of the carbonyl compound. (Carbonyl compounds are more volatile than the corresponding alcohols). Usually the alcohol is in excess of the oxidant and the aldehyde is distilled off to avoid further oxidation.
  • Note the color and smell cautiously (Royal Wave).
  • Warm the mixture and smell cautiously (Royal Wave).
  • Repeat the experiment using first methanol and then propan-2-ol in place of ethanol.

 

Describe what happens and explain the color changes.

What conditions and techniques would favour the oxidation of ethanol to

a. ethanal rather than ethanoic acid.

b. ethanoic acid rather than ethanal?

Oxidation of an alcohol with acidified potassium permanganate (vii) solution

  • Add 10 drops of dilute sulfuric acid and 5 drops of potassium permanganate (VII) solution (0.01M) to 5 drops of ethanol. Note the color and smell cautiously.
  • Warm the mixture and smell cautiously (Royal Wave).
  • Repeat the experiment using first methanol and then propan-2-ol in place of ethanol.
  • Take the pH of your final mixture using Universal indicator paper

 Describe what happens and explain the color changes.

What is your final product?

Saponification of a vegetable oil

CAUTION - Sodium hydroxide is a very caustic material that can cause severe skin burns. Eye burns caused by sodium hydroxide are progressive: what at first appears to be a minor irritation can develop into a severe injury unless the chemical is completely flushed from the eye. If sodium hydroxide comes in contact with the eye, flush the eye with running water continuously for at least 20 minutes. Notify your TA immediately. If sodium hydroxide is spilled on some other parts of the body, flush the affected area with running water continuously for at least 2-3 minutes. Notify your TA immediately.

Questions & Answers

show that the set of all natural number form semi group under the composition of addition
Nikhil Reply
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Dominic
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Lukman Reply
_3_2_1
felecia
⅗ ⅔½
felecia
_½+⅔-¾
felecia
The denominator of a certain fraction is 9 more than the numerator. If 6 is added to both terms of the fraction, the value of the fraction becomes 2/3. Find the original fraction. 2. The sum of the least and greatest of 3 consecutive integers is 60. What are the valu
SABAL Reply
1. x + 6 2 -------------- = _ x + 9 + 6 3 x + 6 3 ----------- x -- (cross multiply) x + 15 2 3(x + 6) = 2(x + 15) 3x + 18 = 2x + 30 (-2x from both) x + 18 = 30 (-18 from both) x = 12 Test: 12 + 6 18 2 -------------- = --- = --- 12 + 9 + 6 27 3
Pawel
2. (x) + (x + 2) = 60 2x + 2 = 60 2x = 58 x = 29 29, 30, & 31
Pawel
ok
Ifeanyi
on number 2 question How did you got 2x +2
Ifeanyi
combine like terms. x + x + 2 is same as 2x + 2
Pawel
x*x=2
felecia
2+2x=
felecia
×/×+9+6/1
Debbie
Q2 x+(x+2)+(x+4)=60 3x+6=60 3x+6-6=60-6 3x=54 3x/3=54/3 x=18 :. The numbers are 18,20 and 22
Naagmenkoma
Mark and Don are planning to sell each of their marble collections at a garage sale. If Don has 1 more than 3 times the number of marbles Mark has, how many does each boy have to sell if the total number of marbles is 113?
mariel Reply
Mark = x,. Don = 3x + 1 x + 3x + 1 = 113 4x = 112, x = 28 Mark = 28, Don = 85, 28 + 85 = 113
Pawel
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Harshika Reply
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Harshika
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Rofiqul
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corri
X=16
Michael
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Mark
16
Makan
x=16
Makan
use the y -intercept and slope to sketch the graph of the equation y=6x
Only Reply
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Seidu Reply
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Darius
hello, if you have a question about Algebra 2. I may be able to help. I am an Algebra 2 Teacher
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Tric Reply
4
Trista
x-2y+3z=-3 2x-y+z=7 -x+3y-z=6
Sidiki Reply
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Mark
Solve for the first variable in one of the equations, then substitute the result into the other equation. Point For: (6111,4111,−411)(6111,4111,-411) Equation Form: x=6111,y=4111,z=−411x=6111,y=4111,z=-411
Brenna
(61/11,41/11,−4/11)
Brenna
x=61/11 y=41/11 z=−4/11 x=61/11 y=41/11 z=-4/11
Brenna
Need help solving this problem (2/7)^-2
Simone Reply
x+2y-z=7
Sidiki
what is the coefficient of -4×
Mehri Reply
-1
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Source:  OpenStax, Honors chemistry lab fall. OpenStax CNX. Nov 15, 2007 Download for free at http://cnx.org/content/col10456/1.16
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