Name of the Centre : Homi Bhabha Centre For Science Education
Name Of The Exam : Indian National Chemistry Olympiad 2017
Name Of The Subject : Chemistry
Document type : Sample Questions Papers
Year : 2017
Website : https://olympiads.hbcse.tifr.res.in/
Download Sample Question Paper : https://www.pdfquestion.in/uploads/13653-INChO2017.pdf
INCO Indian National Chemistry Olympiad Question paper :
Theory (3 hours)
Instructions for students :
** Write your Roll No. at the top of all pages.
Related : Homi Bhabha Centre For Science Education Indian National Biology Olympiad INBO – 2017 Question Paper : www.pdfquestion.in/13650.html
** This examination paper consists of 29 pages of problems including answer boxes.
** Kindly check that the booklet has all the pages.
** Blank space for rough work has been provided at the end of the paper.
** Use only a pen to write the answers in the answer boxes. Anything written by pencil will not be considered for assessment.
** All answers must be written in the appropriate boxes. Anything written elsewhere will not be considered for assessment.
** You must show the main steps in the calculations.
** For objective type question, mark X in the correct box. Some of the objective questions may have more than one correct answer.
** A copy of the Periodic Table of the Elements is provided on the 2nd page of the paper.
** Do not leave the examination room until you are directed to do so.
** The question paper will be uploaded on the HBCSE website on 31st January 2017.
Problem 1 : 17 Marks
Guano, the excreta of sea birds and bats was a major export item from colonial America to Europe in the 19th century used for making fertilizers and extracting uric acid, which was used to produce many commercial chemicals including the valuable dye Murexide. Uric acid is a metabolic by-product of proteins and nucleic acids.
German chemist Adolf von Baeyer in 1864, while studying the chemistry of uric acid, discovered barbituric acid C. Derivatives of this compound were very effective in inducing sleep in animals. Later, this family of compounds turned out to be very effective drugs for human psychological disorders.
In a few years, a simple proc1.3 Compound C is quite acidic (pKa = 4.01). Draw the structures f the most stable tautomers of the conjugate base of C. The tautomers should be unique and not resonance structures of each other.edure to produce C was found using POCl3 mediated condensation of compound A (C3H4O4) derived from apple juice and compound B (CH4N2O), abundant in animal excreta.
1.1 Draw structures for A and B.
1.2 Draw the structure of D and the two isomers of E and label them with „R? and „S? configuration. Compound F (C4H2N2O4) is one of the oldest synthesised organic compounds, discovered by Justus von Liebig and Friedrich Wöhler in 1938. It was used to produce the dye murexide. When ingested, it accumulates in the pancreas damaging insulin-producing cells and causing Type II diabetes mellitus. Due to this, it is used to induce diabetes in laboratory rats in diabetes research.
1.3 Compound C is quite acidic (pKa = 4.01). Draw the structures of the most stable tautomers of the conjugate base of C. The tautomers should be unique and not resonance structures of each other.
1.4 F is formed in the CrO3 oxidation of the condensation product G of benzaldehyde and C in the presence of piperidine (a base). Draw the structures of F and G.
1.5 The condensation reaction above giving G proceeds well. This shows that the pKa of the conjugate acid of piperidine is (mark X in the correct box) a) < 4.01 b) > 4.01 c) = 4.01
1.6 Identify the structures H to J.
1.7 L (C5H10O5) on reduction with sodium borohydride (NaBH4) gives an optically inactive alditol. Draw the Fischer projection formula of L with correct configuration at all chiral carbons.
1.8 One of the chemical syntheses of K involves a series of reactions as given below.
1.9 Degradation studies of K had played an important role in its identification. Alkaline hydrolysis of K with 1 M NaOH at 100oC gave P (C16H19N2NaO7) by losing a mole of B. Further hydrolysis of P by 5M NaOH at 100oC gave Q (C13H22N2O4). Draw structure of P and Q.