IA - Lab Report. Aim to prepare a sample of p-nitro acetanilide from the given acetanilide.

* 10 cm3 measuring flask x3

* Electronic weighing machine x 1

* Watch glass x 1

* Thermometer x 1

* Test tube x 1

* Dropper x 1

* Ice box x 1

* Burner x 1

* Glass rod x 3

* Funnel x 2

* Filter paper as required

* Safety goggles x 1 pair

* Apron x 1 pair

> Chemicals required

* Acetanilide

* Glacial acetic acid

* Concentrated acid

* Concentrated sulfuric acid

* Fuming metric acid

* Methylated spirit

* Ice cubes

* Chilled water

PROCEDURE

* Preparation of the salt solutions

o Weigh 5 g of acetanilide powder in a watch glass with the help of an electronic weighing machine and add this to a 100 cm3 conical flask.

o Use a 10 cm3 measuring flask, measure 5 cm3 of glacial acetic acid and add this to the conical flask mentioned above. Stir it well with the help of a glass rod.

o Then, measure 2 cm3 of fuming nitric acid in another 10 cm3 measuring flask and pour it into a test tube.

o Place this test tube into an ice box for it to cool down.

o Measure 2 cm3 of concentrated H2SO4 in another 10 cm3 flask and with the help of a dropper add this sulfuric acid to the test tube containing the acid.

o In the same measuring flask, measure 8 cm3 of sulfuric acid and using a dropper add this to the conical flask containing acetic acid and acetanilide.

o Place this conical flask into a freezing mixture of water and ice cubes. Stir the contents with a glass rod and keep checking the thermometer for when it reaches 5oC.

o Once cooled, slowly add the contents to a conical flask and keep stirring. Make sure that the temperature doesn't rises above 25oC.

o After letting the flask be in the ice bowl, take it out leave it for 30 minutes.

o With the help of a funnel and a filter paper, scrape out the crude product and then thoroughly wash it with cold water to remove the acid.

o Dissolve the crude product into about 20 cm3 Methylated spirit in another 100 cm3 conical flask and warm the mixture with the help of a burner.

o Filter the solution while still hot and then put the filtrate in ice.

o O-Nitroacetanilide comes out as the filtrate and p-nitroacetanilide is obtained as colorless crystals on the filter paper.

o Wash the obtained solid on the filter paper with cold water, dry it and then weigh it.

MULTIPLE TRIALS

* To be sure of the reading, weigh the crystals twice.

SAFETY

* Gloves should be worn at all times, through out the experiment

* Add the fuming nitric acid slowly drop by drop.

* Refrain for inhaling the vapors of nitric acid as they have a corrosive nature and hence a fume cupboard should be used while mixing acids with other chemicals

* Make sure the temperature does not go above 25oC while mixing the nitrating mixture.

DATA COLLECTION AND EVALUATION Aspect 1

RECORDING DATA

Mass of acetanilide -5 g

Volume of glacial acetic acid -5 cm3

Volume of concentrated sulfuric acid -10 cm3

Volume of fuming nitric acid -10 cm3

Volume of Methylated spirit -20 cm3

The crude product is a dull yellow and becomes thick before the Methylated spirit is added to it.

UNITS

* Weight of a substance - gm

* Volume of the solutions - cm3

UNCERTAINITY

* Electronic weighing machine - +/- 0.005 gm

* Measuring flask - +/- 0.05 cm3

DATA COLLECTION AND PROCESSING Aspect 2

PROCESSING RECORDED

The p-nitroacetanilide obtained is colorless and has a crystalline form with a melting point of 214oC.

Gm +/- 0.005

Weight of the watch glass

21.050

Weight of the p-nitroacetanilide

3.974

Total weight

25.024

CONCLUSION AND EVALUATION Aspect 1

CONCLUSION

By the nitration of aniline, 3.974 g of acetanilide is produced after the amino group is shielded by acylation to form acetanilide and then nitrated, and then the required p-nitroacetanilide is obtained along with o-nitroacetanilide as a minor product.

The soluble ortho compound is removed through re-crystallization and pure p-nitroacetanilide is obtained.

CONCLUSION AND EVALUATION Aspect 2

EVALUATING PROCEDURES

Percentage errors (%) = uncertainty * 100

True value

* Amount of acetanilide taken 0.005 * 100 = 0.1%

(Weighing machine) 5

* Volume of glacial acetic acid = 0.05 * 100 = 1.0%

(Measuring flask) 5

* Volume of HNO3 to test tube = 0.05 * 100 = 1.0%

(Measuring flask) 5

* Volume of H2SO4 added to test tube = 0.05 * 100 = 2.5%

(Measuring flask) 2

* Volume of H2SO4 added to conical flask = 0.05 * 100 = 0.625%

(Measuring flask) 5

* Volume of Methylated spirit = 0.05 * 100 = 0.25%

(Measuring flask) 20

* Mass of the watch glass used = 0.005 * 100 = 0.024 %

(Weighing machine) 21.05

* Total mass of the watch glass and the product = 0.005 * 100 = 0.020%

(Measuring flask) 25.025

Total uncertainty = 7.019

CONCLUSION AND EVALUATION Aspect 3

IMPROVING THE INVESTIGATION

o Equipment with the least chance of causing uncertainties should be used

o The experiment should be performed very meticulously, with the help of a fume cupboard and at the same room temperature and pressure.