Chemistry Laboratory XII

A list of experiments under different headings is given below. Students are required to perform   8-10 experiments (minimum two from each category).

Minor Experiments:

1. To determine the solubility diagram for a three  component liquid system chloroform, acetic acid and water / toluene, acetic acid and water / benzene ethanol and water. To discuss the diagram in light of phase, component and degree of freedom.
2. To study the freezing point curve of two-component simple eutectic system (acetamide-benzoic acid/naphthalene-benzoic acid)
3. To determine the composition of the binary mixture containing K₂Cr₂O₇ & KMnO₄/ crystal violet & aurine / N-butyl acetanilide & benzyl benzoate by spectrophotometric method.
4. To titrate the given mixture of CO₃^-2 and HCO₃^- ions against a strong acid, 0.1N HCl solution and to determine their strength.
5. To determine pKa values of tribasic acid (H₃PO₄) against a strong base (NaOH).
6. To determine the acidic and basic dissociation constant of an amino acid and hence its isoelectric point.
7. To determine of pKa values of maleic/malonic acid by potentiometric titration with NaOH using glass electrode.

Major Experiments:

1. To determine the acid dissociation constant (pKa value) of methyl red.
2. To determine the composition of the binary mixture containing K₂Cr₂O₇ & KMnO₄/ crystal violet & aurine / N-butyl acetanilide & benzyl benzoate by spectrophotometric method.
3. To determine the strength of a base by spectrophotometric method.
4. To analyse a mixture of copper (II) and bismuth (III) ions by colorimetric titration with EDTA.
5. To determine the composition of copper and iorn (III) solution by spectrophotometric titration with EDTA.
6. Nernst Distribution Law: To determine the formula of a complex ion formed between cupric ion and ammonia by distribution method.

 Scheme of Examination

The duration of examination will be 6 hrs.

The following exercise will be set in the examination

Physical Chemistry Experiment (two)                             

Experiment I                                                                          35 marks

Experiment II                                                                         20 marks

Viva                                                                                      15 marks

Total                                                                                         70 marks

1.Physical Chemistry Experiment

The exercises in Physical chemistry can be modified by the examiners and the same will be explained to the candidates. However, such modifications will not involve any departure from the basic principles over which experiments are prescribed in the syllabus. Candidates shall be given 2 exercises out of the exercises prescribed in the syllabus. The distribution of marks will be as follows:

Major experiment

The exercise carries 35 marks. One major experiment by lot will be given to perform. 5 marks shall be awarded for preparatory work, setting up of an apparatus, neat and methodical work. 30 marks will be awarded for correct observation, use of correct formula, calculation and result within permissible limits as follows:

·         Theory and procedure                                          8 marks

·         Correct observation and proper recording              8 marks

·         Use of correct formula and calculation                   8 marks

·         Result                                                                6 marks

Minor experiment

The exercise carries 20 marks. One minor experiment by lot will be given to perform. 4 marks shall be awarded for preparatory work, setting up of an apparatus, neat and methodical work. 16 marks will be awarded for correct observation, use of correct formula, calculation and result within permissible limits as follows:

·         Theory and procedure                                      4 marks

·         Correct observation and proper recording           5 marks

·         Use of correct formula and calculation                 5 marks

·         Result                                                              2 marks

The permissible limit will be decided by the examiner as it varies with the nature of the experiment.

No marks for calculation will be awarded to a candidate for not calculating result.

 The permissible error will depend on the nature of the experiment. Generally + 10% error may be taken as permissible error for experiments involving potentiometric and conductometric measurements. The constancy in values or rate constants may be taken into consideration while awarding mark in experiments on chemical kinetics. One mark shall be deducted for each + 2% error over permissible limit. 

2.Viva

Oral questions shall generally be asked over the work assigned to the candidate. The purpose is to find out as to what extent the candidate has understanding the basic principles of chemistry.