Organic Chemistry Answers

Procedure

1. Use a pipet bulb and a 5-mL transfer pipet to measure EXACTLY 5.00 mL of a commercial bleach solution into a 100-mL volumetric flask.
2. Dilute to the mark with distilled water, stopper, and mix well.
3. Weigh out approximately 2 g solid KI. This is a large excess over that which is needed.
4. Pipet EXACTLY 25.0 mL of the dilute bleach into an Erlenmeyer flask.
5. Add the solid KI and about 25 mL of distilled water. Swirl to dissolve the KI.
6. Working in a fume hood, add approximately 2 mL of 3 M HCl while stirring the solution. The solution should be dark yellow to red-brown from the presence of the I3- complex ions.
7. Fill the buret with 0.100 M sodium thiosulfate solution (this may have already been done for you). Record the initial buret reading and the solution molarity in the Data table.
8. Titrate with the standard 0.100 M sodium thiosulfate solution until the iodine color fades to light yellow.
9. Add one dropperful of starch solution. The blue color of the starch-iodine complex should appear.
10. Continue the titration until one drop of Na2S2O3 solution causes the blue color to disappear. Record the final buret reading in the Data Table.

Question--> How would each of the following laboratory mistake affect the calculated value of the percent NaClO in the commercial bleach (too high, too low, no change)? Explain. a. In step 6, some of the iodine that formed sublimed from the solution. 

Data Table Molarity of Na2S2O3 0.125 M Initial Buret Reading (Na2S2O3) 1.50 mL Final Buret Reading (Na2S2O3) 14.35 mL 

 Calculate the average molarity of commercial bleach before it was diluted.

Explain why the 2-hydroxy-2-methylbutanoic acid produced in this reaction is not optically active.

(The reaction is the incomplete mechanism in the conversion of Butanone into 2-hydroxy-2-methylbutanoic acid)

Give two reasons why methanol, synthesised from carbon dioxide and hydrogen, may not be a completely carbon-neutral fuel.

The high resolution proton nmr spectrum of propan-1-ol contains four peaks. What is the splitting pattern of the four peaks?

A. 3 2 2 1

B. 3 4 3 1

C. 3 6 3 1

D. 3 6 4 2

Reactions of Alkenes

Solve for one major organic product given the following combination of reactants (substrate+reagents)

Substrate: C7H12

Reagent: H2/Pt

Reactions of Arenes

Solve for one major organic product given the following combination of reactants (substrate+reagents).

Substrate: 4-Isopropylbenzoic acid

Reagents: Br2, FeBr3

What is the pH of a 0.350 M solution of lithium citrate? (Ka Citric Acid = 7.4 x 10^-4) 

What is the pH of a 1.15 M solution of methanoic acid? Ka = 1.8 x 10^-4?

25cm³ of a solution containing 4.4grams/litre sodium hydroxide was required to neutralize 17.8cm²of a propanoic acid . Determine the concentration of the propanoic acid in gram's/litre?