B.Sc.I Practical Chart

                                    ESTIMATION OF ANILINE

Aim :

Determine the Amount of Aniline solution in kg / dm³

Given :

            Bottle B           :           Na₂S₂O₃ ( 0.1N )

                        Bottle C           :           Brominating Solution ( Approx. 0.1 N )

                        Bottle D           :           Aniline

Procedure :

Back Titration :

            Take exactly 10 ml of Brominating soln in a stoppered bottle and add about 10 ml of Aniline (by pipette) . Add about 3 ml (¼ TT) conc. HCl and about 25 ml (2 TT) dist. water Shake and wait for about 10 min. Then add about 10 ml 10% KI (1 TT). Titrate immediately the liberated iodine against Na₂S₂O₃. Using starch indicator take 3 Readings and call the const. reading as Y ml. Record the observations

BlankTitration :

            Take exactly 10 ml of Brominating soln in a stoppered bottle and add about 3 ml (¼  TT) conc. HCl and add about 25 ml (2 TT) dist. water. Then add about 10 ml 10% KI (1 TT). Titrate the liberated iodine against Na₂S₂O₃. Using starch indicator take 3 Readings and call the const. reading as X ml. Record the observations and do the calculations.

RESULT :

Strength of Aniline in G/L = ............. gms.   

\kg / dm³ of Aniline = ____________.

 

ESTIMATION OF ANILINE

 

Blank Titration                                                           Back Titration

Soln. in Burette : Na₂S₂O₃(0.1 N)                                 Soln. in Burette : Na₂S₂O₃(0.1 N)

Soln. in stoppered Bottle :                                            Soln. in Stoppered Bottle :

10 ml Brominating soln.                                              10 ml Brominating soln. + 10ml Aniline

+ 1/4 T.T. conc. HCl                                                    + 2 TT Dist. H₂O + 1/4 TT conc. HCl

+ 2 T.T. Dist. Water                                                     Shake and wait for 10 min + 1 T.T. 10% KI

+ 1 T.T. 10% KI

Indicator : Freshly prepared starch soln. (2 ml)            Indicator : Freshly prepared starch soln. (2 ml)

End Point : Blue to colourless                                      End Point : Blue to white ppt

 

Reaction :

1) KBrO₃ + 5KBr + 6 HCl ®                           1) 5 KBr + KBrO₃ + 6 HCl =

    3 Br₂ + 6 KCl + 3H₂O                                       6 KCl + 3H₂O + 3 Br₂

2) Br₂ + 2 KI = 2KBr + I₂                                                     NH₂                        NH₂

3) I₂ + 2Na₂S₂O₃ = Na₂S₄O₆ + 2NaI                                                            Br               Br

 

                                                                                    2)            + 3 Br₂  =                  ¯ + HBr

 

    

    Br

                                                                                    3) Br₂ + 2KI = 2KBr + I₂

                                    4) I₂ + 2Na₂S₂O₃ = Na₂S₄O₆ + 2NaI

Burette Level

Pilot ml.

Burette Readings

C.B.R. ml.

Burette Level

Pilot ml.

Burette Readings

C.B.R. ml.

I

II

III

I

II

III

Final

X ml.

Final

Y ml

Initial

0

0

0

0

Initial

0

0

0

0

Difference

Difference

Calculations :

X ml of 0.1 N Na₂S₂O₃            º          Total Brominating soln.

Y ml of 0.1 N Na₂S₂O₃                º          Unused Brominating soln.

(X – Y) = V ml of Na₂S₂O₃      º          Used Brominating soln. by 10 ml Aniline

 

From Equations :-

2 Na₂S₂O₃        º          I₂          º          Br₂       º          C₆H₅NH₂

\6 Na₂S₂O₃     º          3I₂        º          3Br₂     º          C₆H₅NH₂

\6 Na₂S₂O₃ ,   5H₂O              º          C₆H₅NH₂

\6 x 156 gm Na₂S₂O₃ 5H₂O   º          93 gms of Aniline.

6 x 10,000 ml 0.1 N Na₂S₂O₃ º          93 gms of Aniline.

\V ml of 0.1 N Na₂S₂O₃         º          V x 93 / 60,000 gms of Aniline = ‘g’ gms

G/L of Aniline = ‘g’ x 100 gms.

\kg / dm³ of Aniline = ____________.