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SAMPLE PAPER (2024 -25)
CHEMISTRY THEORY (043)
Max. Marks:70 Time: 3 hours GENERAL INSTRUCTIONS: Read the following instructions carefully. (a) There are 33 questions in this question paper with internal choice. (b) SECTION A consists of 16 multiple-choice questions carrying 1 mark each. (c) SECTION B consists of 5 short answer questions carrying 2 marks each. (d) SECTION C consists of 7 short answer questions carrying 3 marks each. (e) SECTION D consists of 2 case-based questions carrying 4 marks each. (f) SECTION E consists of 3 long answer questions carrying 5 marks each. (g) All questions are compulsory. (h) Use of log tables and calculators is not allowed. SECTION A The following questions are multiple-choice questions with one correct answer. Each question carries 1 mark. There is no internal choice in this section. 1 Ammonolysis of ethyl chloride followed by reaction of the amine so formed with 1 mole of methyl chloride gives an amine that a. reacts with Hinsberg reagent to form a product soluble in an alkali. b. on reaction with Nitrous acid, produced nitrogen gas. c. reacts with Benzenesulphonyl chloride to form a product that is insoluble in alkali. d. does not react with Hinsberg reagent.
2 Which one of the following has the highest dipole moment? a. CH 3 F b. CH 3 Cl c. CH 3 I d. CH 3 Br
3 Match the properties given in column I with the metals in column II Column I Column II (i) Actinoid having configuration [Rn] 5f 7 6d^1 7s^2 (A) Ce (ii) Lanthanoid which has 4f^14 electronic (B) Lu configuration in +3 oxidation state. (iii) Lanthanoid which show +4 Oxidation state (C) Cm
a. (i)-(C), (ii)-(B), (iii)-(A) b. (i)-(C), (ii)-(A), (iii)-(B) c. (i)-(A), (ii)-(B), (iii)-(C) d. (i)-(B), (ii)-(A), (iii)-(C) 4 Study the graph showing the boiling points of bromoalkanes and identify the compounds. a. 1 = Bromomethane, 2= 2-Bromobutane, 3= 1-Bromobutane, 4= 2-Bromo-2-methylpropane b. 1 =1-Bromobutane, 2= 2-Bromo-2-methylpropane, 3= 2-Bromobutane, 4= Bromomethane c. 1 = Bromomethane, 2=1-Bromobutane, 3= 2-Bromo-2-methylpropane, 4= 2-Bromobutane, d. 1 =Bromomethane, 2= 2-Bromo-2-methylpropane, 3=2- Bromobutane, 4= 1-Bromobutane (for visually challenged learners) Which of the following haloalkanes has the highest boiling point? a. 2-Bromo-2-methylpropane b. 2-Bromobutane c. Bromomethane d. 1-Bromobutane
10 A first-order reaction is found to have a rate constant, k = 5.5 × 10-14 s-1. The time taken for completion of the reaction is: a. 1.26 x 10^13 s b. 2.52 x 10^13 s c. 0.63 x 10^13 s d. It never goes to completion
11 A student was preparing aniline in the lab. She took a compound “X” and reduced it in the presence of Ni as a catalyst. What could be the compound “X” a. Nitrobenzene b. 1-Nitrohexane c. Benzonitrile d. 1-Hexanenitrile
12 Which of the following compound gives an oxime with hydroxylamine: a. CH 3 COCH 3 b. CH 3 COOH c. (CH 3 CO) 2 O d. CH 3 COCl
13 Assertion (A): [Mn(CN) 6 ]3–^ has a magnetic moment of two unpaired electrons while [MnCl 6 ]3–^ has a paramagnetic moment of four unpaired electrons. Reason (R): [Mn(CN) 6 ]3–^ is inner orbital complexes involving d^2 sp^3 hybridisation,on the other hand, [MnCl 6 ]3–^ is outer orbital complexes involving sp^3 d^2 hybridisation. Select the most appropriate answer from the options given below: a. Both A and R are true and R is the correct explanation of A b. Both A and R are true but R is not the correct explanation of A. c. A is true but R is false. d. A is false but R is true.
14 Assertion (A) : For strong electrolytes, there is a slow increase in molar conductivity with dilution and can be represented by the equation Reason (R): The value of the constant ‘ A ’ for NaCl, CaCl 2 , and MgSO 4 in a given solvent and at a given temperature is different. Select the most appropriate answer from the options given below: a. Both A and R are true and R is the correct explanation of A b. Both A and R are true but R is not the correct explanation of A. c. A is true but R is false. d. A is false but R is true.
15 Assertion (A) Glucose does not form the hydrogensulphite addition product with NaHSO 3. Reason (R): Glucose exists in a six-membered cyclic structure called pyranose structure. Select the most appropriate answer from the options given below: a. Both A and R are true and R is the correct explanation of A b. Both A and R are true but R is not the correct explanation of A. c. A is true but R is false. d. A is false but R is true.
16 Assertion (A): The half- life for a zero order reaction is independent of the initial concentration of the reactant. Reason (R): For a zero order reaction, Rate = k Select the most appropriate answer from the options given below: a. Both A and R are true and R is the correct explanation of A b. Both A and R are true but R is not the correct explanation of A. c. A is true but R is false. d. A is false but R is true.
SECTION B
This section contains 5 questions with internal choice in one question. The following questions are very short answer type and carry 2 marks each. 17 a. Nitrogen gas is soluble in water. At temperature 293 K, the value of KH is 76.48 kbar. How would the solubility of nitrogen vary (increase, decrease or remain the same) at a temperature above 293 K , if the value of KH rises to 88.8 kbar. b. Chloroform (b.p. 61.2oC) and acetone (b.p. 56oC ) are mixed to form an azeotrope. The mole fraction of acetone in this mixture is 0.339. Predict whether the boiling point of the azeotrope formed will be (i) 60oC (ii)64.5 oC or (iii)54 oC. Defend your answer with reason. OR a. A soda bottle will go flat (loose its fizz) faster in Srinagar than in Delhi. Is this statement correct? Why or why not? b. How does sugar help in increasing the shelf life of the product?
18 a. Write the IUPAC name of the following complex: K[Cr(H 2 O) 2 (C 2 O 4 ) 2 ]H 2 O b. Name the metal present in the complex compound of (i) Haemoglobin (ii) Vitamin B-
b. Write an expression for the molar conductivity of aluminium sulphate at infinite dilution according to Kohlrausch law. 1 23 Account for the following: a. The lowest oxide of transition metal is basic, and the highest is acidic. b. Chromium is a hard metal while mercury is a liquid metal c. The ionisation energy of elements of the 3d series does not vary much with increasing atomic number.
24 a. Give the chemical reaction involved when p-nitrotoluene undergoes Etard reaction. b. Why does Benzoic acid exist as a dimer in an aprotic solvent? c. Benzene on reaction with methylchloride in the presence of anhydrous AlCl 3 forms toluene. What is the expected outcome if benzene is replaced by benzoic acid? Give a reason for your answer. OR An organic compound ‘X’, does not undergo aldol condensation. However ‘X’ with compound ‘Y’ in the presence of a strong base react to give the compound 1,3-diphenylprop-2-en-1-one. a. Identify ‘X’ and ‘Y’ b. Write the chemical reaction involved. c.Give one chemical test to distinguish between X and Y.
25 a. Give the structure of all the possible dipeptides formed when the following two amino acids form a peptide bond. Alanine Glycine b. Keratin, insulin, and myosin are a few examples of proteins present in the human body. Identify which type of protein is keratin and insulin and differentiate between them based on their physical properties.
26 Neeta was experimenting in the lab to study the chemical reactivity of alcohols. She carried out a dehydration reaction of propanol at 140oC to 180oC. Different products were obtained at these two temperatures. a. Identify the major product formed at 140oC and the substitution mechanism followed in this case. b. Identify the major product formed at 180oC and the substitution mechanism followed in this case.
27 Various isomeric haloalkanes with the general formula C 4 H 9 Cl undergo hydrolysis reaction. Among them, compound “A” is the most reactive through SN^1 mechanism. Identify “A” citing the reason for your choice. Write the mechanism for the reaction.
28 The equilibrium constant of cell reaction : Sn4+(.aq) + Al(s) → Al3+^ + Sn2+^ (aq) is 4.617 x 10^184 , at 25 oC a. Calculate the standard emf of the cell. (Given: log 4.617 x 10^184 = 184.6644) b. What will be the Eo^ of the half cell Al3+/Al , if Eo^ of half cell Sn4+/Sn2+^ is 0.15 V.
SECTION D
The following questions are case-based questions. Each question has an internal choice and carries 4 (2+1+1) marks each. Read the passage carefully and answer the questions that follow. (^29) Dependence of the rate of reaction on the concentration of reactants, temperature, and other factors is the most general method for weeding out unsuitable reaction mechanisms. The term mechanism means all the individual collisional or elementary processes involving molecules (atoms, radicals, and ions included) that take place simultaneously or consecutively to produce the observed overall reaction. For example, when hydrogen gas reacts with bromine, the rate of the reaction was found to be proportional to the concentration of H 2 and to the square root of the concentration of Br 2. Furthermore, the rate was inhibited by increasing the concentration of HBr as the reaction proceeded. These observations are not consistent with a mechanism involving bimolecular collisions of a single molecule of each kind. The currently accepted mechanism is considerably more complicated, involving the dissociation of bromine molecules into atoms followed by reactions between atoms and molecules: It is clear from this example that the mechanism cannot be predicted from the
The experimental data is tabulated below: Substituent “X” Electro-n egativity of X substituted piperidine compound pKa Substituted propylamine compound pKa CH 2 2.55 11.13 CH 3 CH 2 CH 2 NH 2 10. NH 3.12 9.81 NH 2 CH 2 CH 2 NH 2 10. O 3.44 8.36 HOCH 2 CH 2 NH 2 9. CH 3 CON 3.6 7.94 CH 3 CONHCH 2 CH 2 NH 2 9. C 6 H 5 CON 3.
C 6 H 5 CONHCH 2 CH 2 NH 2
(source: Hall Jr, H. K. (1956). Field and inductive effects on the base strengths of amines. Journal of the American Chemical Society , 78 (11), 2570-2572.) Study the above data and answer the following questions: a. Plot a graph between the electronegativity of the substituent vs pKb value of the corresponding substituted propyl amine (given that pKa + pKb =14). Is there any relation between the electronegativity of the substituent and its basic strength? b. The electronegativity of the substituent “C 6 H 5 CON” is 3.7, what is the expected pKa value of compound C 6 H 5 CONHCH 2 CH 2 NH 2?
(i) 9.9 (ii) 9.5 (iii) 9.3 (iv) 9. c. The pKa value of the substituted piperidine formed with substituent “X” is found to be 8.28. What is the expected electronegativity of “X” (i)3.5 (ii)3.4 (iii)3.8 (iv) 3. OR What is the most suitable pKa value of the substituted propylamine formed with substituent “X” with electronegativity 3. (i)10.67 (ii)10.08 (iii)10.15 (iv)11. (for visually challenged learners) a.How does the electronegativity of the substituent affect the pKb value and the basic strength of the substituted propyl amine (given that pKa + pKb =14).? Give a reason to support your answer. b. The electronegativity of the substituent “C 6 H 5 CON” is 3.7, what is the expected pKa value of compound C 6 H 5 CONHCH 2 CH 2 NH 2? (i) 9.9 (ii) 9.5 (iii) 9.3 (iv) 9. c. The pKa value of the substituted piperidine (compound 1) formed with substituent “X” is found to be 8.28. What is the expected electronegativity of “X” (i)3.5 (ii)3.4 (iii)3.8 (iv) 3. OR What is the most suitable pKa value of the substituted propylamine formed with substituent “X” with electronegativity 3. (i)10.67 (ii)10.08 (iii)10.15 (iv)11.
SECTION E
The following questions are long answer types and carry 5 marks each. All questions have an internal choice. 31 a. A purple colour compound A, which is a strong oxidising agent and used for bleaching of wool, cotton, silk and other textile fibres was added to each of the three test tubes along with H 2 SO 4. It was followed by strong heating.
(ii) Cresols are less acidic than phenol. b. Williamson’s process is used for the preparation of ethers from alkyl halide. Identify the alkyl bromide and sodium alkoxide used for the preparation of 2- Ethoxy-3-methylpentane c. Convert: (i) Toluene to 3-nitrobenzoic acid. (ii) Benzene to m-nitroacetophenone. OR a. Out of formic acid and acetic acid, which one will give the HVZ reaction? Give a suitable reason in support of your answer and write the chemical reaction involved. b. Alcohols are acidic but they are weaker acids than water. Arrange various isomers of butanol in the increasing order of their acidic nature. Give a reason for the same. c. An organic compound A which is a Grignard reagent is used to obtain 2-methylbutan-2-ol on reaction with a carbonyl compound ‘B’. Identify A’ and ‘B’. Write the equation for the reaction between A and B.
33 a. An experiment was carried out in the laboratory, to study depression in freezing point. 1M aqueous solution of Al(NO 3 ) 3 and 1 M aqueous solution of glucose were taken. From the given figure identify solution 1 and solution 2. Give a plausible reason for your answer. b. The osmotic pressure of a solution of cane sugar was found to be 2.46 atm at 300 K. If the solution was diluted five times, calculate the osmotic pressure at the same temperature. How can the osmotic pressure of the given cane sugar solution be decreased without changing its volume? Give a reason for your answer. OR
a. While giving intravenous injections to the patients, the doctors take utmost care of the concentration of the solution used. Why is it necessary to check the concentration of the solution? b. A solution of phenol was obtained by dissolving 2X 10-2^ kg of phenol in 1 kg of benzene. Experimentally it was found to be 73 % associated. Calculate the depression in the freezing point recorded. (for visually challenged learners) a. Which of the two solutions : 1M aqueous solution of Al(NO 3 ) 3 or 1M aqueous solution of glucose will show a greater depression in freezing point? Give a plausible reason for your answer. b. The osmotic pressure of a solution of cane sugar was found to be 2.46 atm at 300 K. If the solution was diluted five times, calculate the osmotic pressure at the same temperature. How can the osmotic pressure of the given cane sugar solution be decreased without changing its volume? Give a reason for your answer. OR a. While giving intravenous injections to the patients, the doctors take utmost care of the concentration of the solution used. Why is it necessary to check the concentration of the solution? b. A solution of phenol was obtained by dissolving 2X 10-2^ kg of phenol in 1 kg of benzene. Experimentally it was found to be 73 % associated. Calculate the depression in the freezing point recorded.
