Submission of Proposal under Star College Scheme

Procedure:
I. Calibration Curve:

1. 
   Transfer 2.5, 5.0,7.5,10.0, and 12.5 cm3 of standard nickel solution ( 20 pg/ cm3) in five different standard measuring flasks and add 5 g of citric acid in each flask.
   
2. 
   Add distilled water to make up the volume to 100 cm3 and add dilute ammonia solution to obtain PH 7.5
   
3. 
   Cool and transfer each solution to a separate 250cm3 separating funnels.
   
4. 
   Add 20 cm3 DMG solution. Shake well and after standing for 1-2 minutes, add 10 cm3 of chloroform to it.
   
5. 
   Shake individually every funnel for 1 minute. Allow the phases to settle. Separate the yellow chloroform layer in each case and collect it in 25 cm3 standard measuring flask.
   
6. 
   Repeat the extraction of aqueous phase with additional 10 cm3 of chloroform and collect the chloroform extract in the same 25 cm3 standard measuring flask.
   
7. 
   Dilute each solution to the mark with chloroform.
   
8. 
   Measure absorbance of each solution at 366 nm against blank reagent.
   
9. 
   Constuct a calibration curve from the above readings.
   

II. Estimation of unknown Ni(II) solution.

1. 
   Dilute the supplied sample solution of unknown concentration to 250 cm3 with distilled water.
   
2. 
   Transfer 10 cm3 of the diluted solution in a 250 cm3 beaker.
   
3. 
   Treat the solution in the same manner as explained earlier.
   
4. 
   Determine the concentration of nickel ion in the sample solution with the help of calibration curve.
   

III Observation Table

Flask No.	Volume of (cm3)			Concentration of Ni+2 ions in pg/ 25 cm3		Absorbance
	Standard nickel	0.1 % DMG	Final
0	0.0	20	25	0.0
1	2.0	20	25	4.0
2	4.0	20	25	6.0
3	6.0	20	25	12.0
4	8.0	20	25	16.0
5	10.0	20	25	20.0
6	10.0 ( Sample)	20	25	(Unknown)

Graph:
Plot a graph of concentration of nickel in µg against absorbance and determine concentration of sample.
Calculations: The amount of nickel present in 10 cm3 of the given sample solution ( from graph) = x µg.
10 cm3 of the diluted sample solution = x µg of Ni(II)
250 cm3 of the diluted sample solution = 25 x µg of Ni(II)
Amount of Ni(II) present in the given solution = 25 x µg = (25 x) 10-3 mg.


Result:
Amount of Ni(II) present in the given solution =
Project: 8
N – Acetylation of aromatic primary amine


Aim:
To prepare acetanilide from aniline.


Theory:
Replacement of active hydrogen of –NH2 group by an acyl group (-COCH3) is called N-acetylation of primary amine. Acetylation can be carried out by using acetic anhydride or acetyl chloride.


Reaction:



Procedure:

1. 
   Place the given quantity of aniline, 4ml of acetic anhydride and a drop of conc. H2SO4 in 250ml conical flask.
   
2. 
   To the aniline solution add 3cm3of acetic anhydride with constant stirring.
   
3. 
   Heat the reaction mixture on boiling water bath for 15-20 min pour the contents into 50cm3 of ice cold water.
   
4. 
   Filter the solid product with suction pump or common. Wash with cold water.
   
5. 
   Recrytallize the product from hot distilled water.
   
6. 
   Dry and weight and determine m.p. of the purified product.
   

Observation & Calculation:
Density of aniline = 1.023 g/cm³
Weight of product = _________ gm


Theoretical Yield:
93gm of aniline gives 135gm of acetanilide
= __________________(Y)g of acetanilide.
Value of V (in cm³) will be supplied.


Percentage Yield:
Y gm of product corresponds to 100% yield
X g ---------------- = ______________ Z %
Rf value


Result:

1. 
   Melting point of the product = ____________⁰ C
   
2. 
   Weight of product =_____________ g
   
3. 
   Theoretical yield =_____________ g
   
4. 
   Percentage yield =_____________%
   
5. 
   Rf value (Match) given product = _____________
   

Project: 9