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U-7
EXPERIMENTAL PROCEDURE
Part I: Solubility and Extent of Ionization
Obtain a well dish and wash it thoroughly with hot tap water, then rinse using deionized water. Drain the wells,
but do not dry. Note that the positions of the wells are labeled, A to D on the short axis, and 1 to 6 along the long
axis.
A.
1.
Label two 13 x 100 mm test tubes, A and B. Add a small scoop (about the size of a pea) of NaCl to each
test tube. Check that there is the same height of solid in each test tube. Add
2 mL of water to A, and 2 mL of dichloromethane to B. Stopper them and shake. Record your results
on your Observations Sheet. Using a clean Pasteur pipet, transfer about 1.5 mL of the water from test
tube A into well B-1 of the well plate. Using another clean Pasteur pipet, transfer about 1.5 mL of the
dichloromethane from test tube B into well B-4.
2.
Now, add 2 mL of dichloromethane to the solution remaining in test tube A, and 2 mL of water to the
solution remaining in test tube B. Stopper the tubes and shake the solution. In each case, the solute would
be drawn into the solvent in which its solubility is greater. Record your results on your Observations
Sheet.
3.
Using a clean Pasteur pipet, transfer 1.5 mL of the dichloromethane (top layer) from test tube A into well
C-l of the well plate. Using another clean Pasteur pipet, transfer 1.5 mL of the water (bottom layer) from
test tube B into well C-4.
B.
1.
Label two clean test tubes, C and D. Put 2 mL of bromine water, Br
2(aq)
, into test tube C, and 2 mL, of
iodine water, I
2(aq)
, into test tube D. Now add 2 mL of dichloromethane to each test tube. Stopper these
two test tubes and shake for one minute. Record the colors of the aqueous and dichloromethane
layers on your Observations Sheet.
2.
Using automatic dispenser, put 1.5 mL of pure dichloromethane into well D-5. Using a clean Pasteur
pipet, transfer about 1.5 mL of the dichloromethane (top layer) from test tube C into well D-l. Next,
transfer about 21.5 mL of the aqueous layer (bottom layer) into well D-2.
3.
Clean the Pasteur pipet and transfer about 1.5 mL of the dichloromethane (top layer) from test tube D
into well D-4. Next, using the same Pasteur pipet transfer about 1.5 mL of the aqueous layer (bottom
layer) into well D-3.
