Transcript EXPERIMENT 13

EXPERIMENT 13
PROCEDURES
1. Chromic Acid test
1. Prepare three test tubes, put 20 drops of nbutyl alcohol on the 1st test tube, sec-butyl
alcohol on the 2nd and tert-butyl alcohol on the
3rd, LABEL each test tube accordingly.
2. Put 10 drops of 5% potassium dichromate
and 10 drops of 5% sulfuric acid on each of the
test tubes.
3. Prepare a boiling water bath, and put the test
tubes. Prepare a timer and record the time as
each of the test tubes change color. Also record
the color and odor of each of the solutions.
2. LUCAS TEST
• Prepare four test tubes, put 20 drops of tertbutyl alcohol on the 1st , sec-butyl alcohol on
the 2nd, n-butyl alcohol on the 3rd, and benzyl
alcohol on the 3rd.
• Add 20 drops of freshly made LUCAS REAGENT
on each of the test tubes. Shake once and let
it rest.
• Prepare the timer, and record the time as the
insoluble layer (emulsion) forms on each of
the test tube, tis indicates the production of
alkyl halide.
Alcohol
Alcohols are compounds containing the hydroxyl (OH) functional group bonded to an alkyl, R and thus
may be represented by the general formula ROH.
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Reactivity is mainly attributed to the -OH
group.
Has an inherent acid character shown when
the hydrogen is released from the -OH bond.
May also be protonated at the oxygen, which
weakens the C-O bond so that the whole
group may be cleaved off as water and
subsequently replaced in the molecule
Procedure 3
Materials needed:
Chemicals needed:
Test tube and dropper
Methanol
Salicylic acid
Concentrated sulfuric acid
ESTERIFICATION
Steps:1. Put 20 drops of Methanol in a dry test tube
2. Add 10 drops of Salicylic acid
3. Add 5 drops of Concentrated sulfuric acid
p.s: Observed the odor and time for the odor to develop
4. Methyl alcohol
(Reaction with Copper)
• 10 drops of Methyl alcohol with 10 drops of
Distilled water mixed in a vial.
• Heat a Copper spiral over a Bunsen flame,
then dip it to the methyl alcohol-water
mixture. Repeat this step 20-25 times.
• Carefully add 1 drop of 0.5% resorcinol and 10
drops of concentrated sulfuric acid.
*do not shake
P.S.: note the color change produced at the
junction of the two layers
5. Iodoform Test
• Iodoform is the organ iodine compound with
the formula CHI3. A pale yellow, crystalline,
volatile substance, it has a penetrating odor
(in older chemistry texts, the smell is
sometimes referred to as the smell of
hospitals) and, analogous to chloroform,
sweetish taste. It is occasionally used as
a disenfectant.
a. To 4 drops of ethyl alcohol, add 4 ml of iodine
solution. Then add drop by drop 10% NaOH
until the iodine is decolorized.
b. Place the test tube in a warm bath (60◦c).
c. Repeat the test with: 1. isopropyl alcohol, 2.
methyl alcohol in place of ethyl alcohol.
Test for Glycerol
A. Solubility in water and ether
1. Add 3 mL of water/ether in small portions, to
the test compound in a dry test tube.
2. Shake vigorously after each portion is added.
3. From the addition of the first portion, record
the time required for the solute to dissolve.
4. Determine whether the sample is soluble,
slightly soluble or insoluble based on
recorded time.
B. Acrolein Test
• Place two drops of glycerol in a dry test tube
and add a pinch of KHSO4. Heat the test tube
over the flame. Note the odor produced.
What is Esterification??
Esters are derived from carboxylic acids. A carboxylic acid
contains the -COOH group, and in an ester the hydrogen in this
group is replaced by a hydrocarbon group of some kind. We
shall just be looking at cases where it is replaced by an alkyl
group, but it could equally well be an aryl group (one based on
a benzene ring). Esters have a very sweet fruity smell.
Naturally occurring esters are found in fruits.
When salicylic acid reacts with methanol , Methyl salicylate is
formed. C6H4(OH)COOCH3 or C8H8O3
Procedure 7
Material needed:
Cork with U-shaped glass tubing
2x Erlenmeyer Flask
Test tube
Beaker
Bunsen burner
Ice
Yeast
Pineapple Chunks
Chemicals needed:
Lime water
5% Potassium dichromate
5% Sulfuric acid
Fermentation
10. an
Collect
the distillate
Steps: 1.Slice
overripe
pineapplewhen
into the temperature
reachesskin).
78-79 °C
chunks (without
And
then blend11.Test
them.the distillate for
the presence
of alcohol
2. Filter
out the juice.
using flammability
3. Measure
the volumetest
and
chromicand
acid test. add
of the juice
obtained
5 grams of Baker's yeast for every
500 mL of the juice. Mix
thoroughly.
4. Set up your apparatus as shown on the left image.
8. Carefully separate the liquid in the flask after decanting it for 5 days.
5. Place the mixture in the Erlenmeyer flask.
9.Transfer the obtained liquid to a a new erlenmeyer flask and then add 2-3
6. Then place some lime water in a test tube.
pieces of boiling chips.
7. Set aside for 5 days.
Extra Info about Fermentation
The overall process of fermentation is to convert glucose sugar (C6H12O6) to alcohol
(CH3CH2OH) and carbon dioxide gas (CO2). The reactions within the yeast cell which
make this happen are very complex but the overall process is as follows:
C6H12O6 ====> 2(CH3CH2OH)
Sugar
====>
Alcohol
(Glucose)
(Ethyl alcohol)
+
2(CO2) + Energy (which is stored in ATP)
+ Carbon dioxide gas + Energy