gpsc.gujarat.gov.in Administrative Service Main Exam Chemistry Sample Paper : Public Commission

Organisation : Gujarat Public Service Commission
Post : Main Exam, Gujarat Administrative Service Class-1 & Class-2
Document Type : Sample Paper
Subject : Chemistry
Website : https://gpsc.gujarat.gov.in/Archieved/sample-papers.html
Download Model/Sample Question Paper : https://www.pdfquestion.in/uploads/25565-chemistry.pdf

GPSC Main Exam Chemistry Sample Paper

Main Examination :
English Medium :

Related : GPSC Gujarat Administrative Service Main Exam Physics Sample Paper : www.pdfquestion.in/25561.html

Time : 3 Hours
Total Marks : 200

Instructions

(1) The question paper has been divided into three parts, A, B and C. The number of questions to be attempted and their marks are indicated in each part.

(2) Answers of all the questions of each part should be written continuously in the answer sheet and should not be mixed with other parts’ Answer. In the event of answer found, which are belongs to other part, such answers will not be assessed by examiner.

(3) The candidate should write the answer within the limit of words prescribed in the parts A, B and C.
(4) If there is any difference in English language question and its Gujarati Translation, then English language question will be considered as valid.

(5) Answer should be written in one of the two languages. Write in the language (English or Gujarati) preference given by you. Answer should not be written in both the languages in the same paper.

Sample Question

Instructions :
(1) Question No. 1 to 20.
(2) Attempt all 20 questions.
(3) Each question carries 2 marks.
(4) Answer should be given approximately in 20 to 30 words.

Part – A

1. State and explain Heisenberg’s uncertainty principle.

2. Which of the following will have higher lattice energy and why ?
(i) LiF and MgO (ii) BeO and BaO
3. Discuss the positions of the elements Ni (atomic mass 58.693) and Co (atomic mass 58.933) in the periodic table with justification.

4. Briefly explain the crystal field theory.
5. Explain why the strong field producing ligand CN– ion does not form octahedral [Ni(CN–)6]4– ions.

6. The size of actinide ions decreases regularly along the series. What is the effect known as ? How it is expected to influence the chemistry of the third transition series ?
7. How many stretching and bending modes are possible for a linear triatomic molecule like AB2 ?

8. Draw the first order 1H NMR spectrum of 1, 1, 2-tribromoethane.
9. Classify the following compounds as aromatic or non-aromatic and give reasons.
10. Why primary alkyl halides do not undergo SN1 or E1 reactions ?
11. In one reaction 2-hydroxypropanal and in another cyclohexanone are heated with hydroxylamine and acetic anhydride. Give equations and name the reactions.

12. Write the product in the following reaction and identify the name reaction : CH3CH2CHO + CH3CH(ZnBr)COOCH3 ? A
13. What are antiaromatic compounds in terms of Huckel rule ? Which is antiaromatic: cyclopentadienyl cation or cyclopentadienyl anion ?

14. State and explain the importance of the third law of thermodynamics.
15. Show graphically, the effect of pressure on chemical adsorption of a gas on a solid surface.
16. Write Michaelis-Menten equation. What does KM stand for ?

17. Consider a first order decomposition reaction : A ? P Write the Lindemann mechanism for the above change.
18. Hydrogen molecule breaks into atoms by UV light (? = 253.7 nm) in the presence of mercury. Which photochemical pathway is adopted in the above change ?

19. State and give mathematical expression for lowering of vapour pressure.
20. Can one store 1 M copper sulphate solution in a nickel vessel ? Given E°(Ni2+, Ni) and E° (Cu2+, Cu) are – 0.25 and + 0.34 V respectively.

Part – B

Instructions :
(1) Question No. 21 to 32.
(2) Attempt all 12 questions.
(3) Each question carries 5 marks.
(4) Answer should be given approximately in 50 to 60 words.

21. (a) Write the energy equation for particle in one dimensional box. How it is related to the size of the box ?
(b) State any three features of the solution to the above equation.

22. Draw neat Molecular Orbital Energy level diagram for CO. Explain why C atom is the donor even in presence of O in metal carbonyls.
23. Give structures and colours of all the possible isomers of [Co(en)2Cl2]+. Explain.

24. Complete the following chemical reaction for a given non-aqueous solvent :
(a) Hg2Cl2 + 2NH3(l)
(b) K2[Pt(CN)4] + 2 K NH3(
(c) AsCl5 + SO2 (l)
(d) C6H6 + C6H5COCl

25. Give a comparative account of the 1H NMR spectra of two isomers (A and B) of formula C3H6O. Compound A reacts with Cu(OH)2 to give a carboxylate ion while B does not react.
26. What is sigmatropic rearrangement ? Give one example each for (1, 3) and (2, 3) sigmatropic rearrangements.
27. Identify the name reactions and the product for the following chemical changes :
(a) CH3CH2CH2CHO + CH3COOH
28. What are sols ? Explain the types of sols with examples.

29. State and explain the second law of photochemistry.
30. What is half-life of a chemical reaction ? The half-life of a substance in a first order reaction is 15 minutes. Calculate the rate constant.

31. What is an irreversible process and how many types of irreversible process exists ? Give two examples.
32. What are Ion Selective Electrodes ? Mention their advantages and disadvantages.

Part – C

Instructions :
(1) Question No. 33 to 39.
(2) Attempt any 5 out of 7 questions.
(3) Each question carries 20 marks.
(4) Answer should be given approximately in 200 words.

33. (a) An opium alkaloid (A) containing phenanthrene nucleus forms diacetate called heroin.
(A) reacts with one mole of CH3I. It also gives FeCl3 test and dissolves in NaOH(aq), to form monosodium salt. The sodium salt gives alkaloid back by action of CO2. Halogen acid converts alkaloid into monohalogeno derivative. When treated with CH3I in the presence of KOH(aq), the methylation of alkaloid takes place to form C18H21NO3 (B), which is soluble in alkali.

(B) on oxidation with CrO3 is oxidized to a ketone. Both (A) and (B) can add one H2 molecule each using Pd as a catalyst. Based on the above stated properties of the alkaloid answer the following :
(i) Identify (A) and (B)
(ii) What structural information is obtained about (A) and (B) from the given chemical properties ? Give justification. (15 marks)
(b) Write the structural features of cyanocobalamin. (5 marks)

34. (a) Cr forms [Cr(CO)x] metal carbonyl. Using EAN rule find the value of x in this metal carbonyl. Why a similar vanadium analogue reduces to vanadium carbonylate anion to form stable metal carbonyl ? (5 marks)
(b) The C-C bond length in ethane, graphite, benzene and ethane are found to be 154 pm, 142 pm, 139 pm and 134 pm respectively. Explain.

(c) Using MOT, explain why B2 is paramagnetic. (5 marks)
(d) Bond length of O2 + is smaller than that of O2, whereas that of N2 + is larger than that of N2. Explain. (5 marks)

35. (a) Starting from van’t Hoff equation show that ln k = – Ea/RT + lnA (7 marks)
(b) Write the integral rate equations (do not derive) for zeroth, first and second order reactions along with units of k. From these derive expressions for half-life in each case. Which of these is applicable to radioactive disintegration ? (7 marks)
(c) Write the mechanism of photochemical reactions: Hydrogen-Chlorine and Hydrogen-Bromine. Comment on their quantum yields.

36. (a) Derive Gibbs Helmholtz equation :
(b) Using Clapeyron equation predict the change in melting point of a substance, when the external pressure on the substance is raised, given that the solid substance floats on the liquid phase of the substance. (8 marks)
(c) Neatly draw Weston Cadmium cell and label the parts. (7 marks)

37. (a) Distinguish homogeneous and heterogeneous catalysis. (5 marks)
(b) Briefly discuss the important features of enzyme activity. (5 marks)
(c) Derive Langmuir adsorption isotherm and give its limitations. (10 marks)

38. (a) Explain the principle of Raman spectroscopy. (6 marks)
(b) The mass spectrum of bromopropane exhibits two peaks of almost equal abundance at m/z 122 and 124. Base peak is observed at m/z 43. Explain the observation and their formation. (6 marks)

(c) A complex [Co(en)2NO2Cl]+ has two geometrical isomers (A) and (B). (A) reacts with excess of oxalic acid to form [Co(en)2ox]+ whereas (B) forms [Co(en)2 (ox)2]–. Identify (A) and (B). Which of the geometrical isomers will be optically active and why ? (6 marks)

(d) Write IUPAC names of the following :
(i) [Pt(NH3)4] [Pt(ox)2]
(ii) [Fe(CN)5NO]2 (SO4)3 (2 marks)

39. (a) What is trans effect ? Suggest a way to synthesize cis-and trans-[PtCl2(NH3)2] from [Pt(NH3)4]2+ and [PtCl4]2–. (10 marks)
(b) For the complex [Cr(H2O)6]2+, the mean pairing energy is 23500 cm–1 and themagnitude of ?0 is 13900 cm–1. Calculate the CFSE for the complex in low and high spin state. Which spin state is more stable in this case ?

(c) Write short note on lanthanide contraction. (5 marks)