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ISC Board Specimen 2015 : Chemistry Paper 2 (Practical III of V)

3 pages, 17 questions, 1 questions with responses, 1 total responses,    1    0
ISC 12th
Indian School Certificate Examination (ISC), New Delhi
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SPECIMEN PAPER III OF V CHEMISTRY PAPER 2 (PRACTICAL) (Three hours) (Candidates are allowed additional 15 minutes for only reading the paper. They must NOT start writing during this time.) ---------------------------------------------------------------------------------------------------------------ALL ANSWERS MUST BE WRITTEN IN THE ANSWER BOOKLET PROVIDED SEPARATELY. Question 1 is an oxidation-reduction titration in which sufficient working details are given. All essential working must be shown. Question 2 is based on experiments on distinction between carbohydrates and proteins and pH determination. Question 3 is an exercise in qualitative analysis. ---------------------------------------------------------------------------------------------------------------Read the questions carefully and follow the given instructions. Attempt all questions. All working, including rough work, should be done on the same sheet as the rest of the answer. The intended marks for questions or parts of questions are given in brackets [ ]. Mathematical Tables are provided. ---------------------------------------------------------------------------------------------------------------Attempt all questions. Question 1 [8] You are provided with two solutions as follows: C-10 is a solution prepared by dissolving 1.04 gms of potassium manganate (VII) KMnO4 per litre. C-11 is a solution prepared by dissolving 13.4 gms of hydrated ammonium iron (II) sulphate crystals, (NH4)2SO4.FeSO4.xH2O per litre. PROCEDURE: Rinse and fill the burette with the solution C-10 (KMnO4). Pipette out 20 ml or 25 ml of C-11 (hydrated ammonium iron (II) sulphate) into a clean conical flask. To this, add 20ml of dilute sulphuric acid C-12, specially provided for titration. Titrate the solution with C-10 (KMnO4) till one drop of this gives a light permanent pink colour to the solution in the conical flask. Ensure that the pink colour does not disappear on shaking the contents of the conical flask. Repeat the experiment to get at least two concordant readings. Tabulate your readings. ---------------------------------------------------------------------------------------------------------------------------53 ISC SPECIMEN QUESTION PAPER 2015 State: (a) The capacity of the pipette used. (b) The titre value you intend to use in your calculations. Show the titre value to the Visiting Examiner. The equations for the above reactions are as follows: 2KMnO4 + 3H2SO4 K2SO4 + 2MnSO4 + 3H2O + 5[O] 10(NH4)2SO4.FeSO4.xH2O+5H2SO4 + 5[O] 10(NH4)2SO4 + 5Fe3(SO4)3+ 10 xH2O + 5H2O Relative atomic masses: K = 39 Fe = 56 S = 32 N = 14 H=1 Mn = 55 O = 16 Calculate the following: (i) The molarity* of potassium manganate (VII) solution C-10. (ii) The molarity* of hydrated ammonium iron (II) sulphate solution C-11. (iii) The molecular mass of hydrated ammonium iron (II) sulphate deduced from the experimental data. (iv) The numerical value of x. *Note: Molarity must be calculated upto at least 4 decimal places. **Question 2 (a) [5] Substances C-13 and C-14 are unknown samples of carbohydrate and protein. Carry out the following experiments and record all your observations. State the identity of the compound on the basis of the experiments and observational changes: Take a pinch of each of the samples in different test tubes labelled as C-13 and C-14. Dissolve each in 10ml distilled water. Divide each solution into three parts. (i) To the first part of C-13 and C-14 add 1ml of Tollen s reagent and place the test tubes in a beaker of boiling water for two minutes. (ii) To the second part of C-13 and C-14 add two drops of alcoholic -naphthol solution followed by 1ml concentrated H2SO4 carefully down the side of the test tube. (iii) To the third part of C-13 and C-14 add two drops of concentrated HNO3 and observe the change. ---------------------------------------------------------------------------------------------------------------------------54 ISC SPECIMEN QUESTION PAPER 2015 (b) Solutions C-15 and C-16 are samples of acids. Carry out the following experiment and note the colour changes taking place. State the nature of the acid and the pH of the solutions C-15 and C-16. PROCEDURE: Dip strips of pH paper (as provided) into solutions C-15 and C-16 separately. Take out the pieces of pH papers and compare the colour with the colour chart provided. **Note: Question 2 will be set from any one OR a combination of any two of the following: Rate of Reaction Identification of Organic Compounds pH determination Test for carbohydrates and proteins. Question 3 [7] Analyse qualitatively the substance C-17 which contains two anions and two cations. Identify these ions. (a) While testing for anions you must mention: (i) How the solution/soda extract was prepared. (ii) How the gases were identified. (iii) The confirmatory test for anions. Show the results as required to the Visiting Examiner. (b) While testing for cations you must mention: (i) How the original solution for group analysis was prepared. (ii) The formal group analysis with pertinent group reagents. (iii) The confirmatory test for each cation. Show the results as required to the Visiting Examiner. Note: Use of qualitative analysis booklet/table is not allowed. Question 4 Show the following to the Visiting Examiner for assessment: (a) Project [7] (b) Chemistry Practical File. [3] ---------------------------------------------------------------------------------------------------------------------------55 ISC SPECIMEN QUESTION PAPER 2015

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Additional Info : ISC Board Specimen Question Paper 2015 Chemistry Paper 2 Practical III of V
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