Aim:

The objectives of this experiment were to gain knowledge on how to titrate solution and determine amount of Vitamin C in Ribena.

Results

Table 1: Mass of Ascorbic Acid in Volumetric Flask

Mass of empty bottle (g) 21.5922

Mass of empty bottle with ascorbic acid (g) 21.6954

Mass of empty bottle (g) 21.5924

Mass of ascorbic acid used (g) 0.1002

Number of moles: (mass of ascorbic acid used)/(molecular mass of ascorbic acid) = 0.1002g/(176.10gmol-1) = 5.69 x10-4 moles

M1: concentration of stock ascorbic acid V1: volume in volumetric flask with stock solution

M2: concentration of diluted ascorbic acid V2: volume in volumetric flask with diluted solution

(M1 x 100)/1000 = 5.69 x10-4 moles M1: 5.69 x10-3 mol/L

M1V1 = M2V2

5.69 x10-3 mol/L x (10/1000) = M2 x (100/1000) M2: 5.69 x10-4 mol/L

Table 2: Standardization of NBS

Titration number Rough 1 2 3

Final burette reading (ml) 16.80 27.00 37.20 47.30 ±0.10

Initial burette reading (ml) 5.40 16.80 27.20 37.20 ±0.10

Titre (ml) 11.40 10.80 10.00 10.10

Number of OK titres, N

Sum of OK titres 2.00

Average (ml) 10.05

Calculation:

(10.00+10.10)/2 = 10.05

M1V1 = M2V2

M1: concentration of diluted ascorbic acid V1: volume of diluted solution in conical flask

M2: concentration of NBS V2: volume needed for titration

5.69 x10-4 mol/L x (10/1000) = M2 x (10.05/1000) M2: 5.66 x 10-4 mol/L

Table 3: Quantity of Vitamin C in Ribena

Titration number Rough 1 2

Final burette reading (ml) 12.20 18.60 25.00 ±0.00

Initial burette reading (ml) 5.70 12.20 18.60 ±0.00

Titre (ml) 6.50 6.40 6.40

Number of OK titres, N

Sum of OK titres 2.00

Average (ml) 6.40

Moles of NBS: MV

5.66 x 10-4 mol/L x (6.40/1000) = 3.62 x 10-6 moles

M1V1 = M2V2

M1: concentration of NBS solution V1: volume of NBS needed for titration

M2: concentration of Vitamin C in ribena V2: volume of ribena added

5.66 x 10-4 mol/L x (6.40/1000) = M2 x (2/1000)