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26. In a fcc lattice of X and Y, X atoms are present at the corners while Y atoms are present at the face centres. If one of the X atom from a corner is replaced by monovalent Z atom, then the formula of compound is given as X a Y b Z. Here a is Comprehension Type Understand carefully the following two reactions and answer the questions given below : Reaction (i) NHCOCH 3 Reaction (ii) Step 1 Step 2 → → CH 3 Step 1 → Step 2 → → → NH 2 SO 2 NH 2 CH 3 SO 2 NCl – Na + 27. Which of the steps is common in the two reactions? (a) 1st step (b) 2nd step (c) Both the steps (d) None of the steps 28. Which of the final products are medicinally important? (a) Product from reaction (i) (b) Product from reaction (ii) (c) Product from both reactions (d) None of the above Matrix Match Type 29. Match the compounds given in Column I with their shapes in Column II. Column I Column II (A) XeO 3 (P) Trigonal pyramidal (B) XeOF 4 (Q) Linear 3– (C) BO 3 (R) Square pyramidal (D) I 3 –(aq) (S) Trigonal planar A B C D (a) P Q R S (b) S P Q R (c) P R S Q (d) P S R Q 30. Match the reactions given in Column I with the steps involved in mechanism in Column II. Column I Column II (A) Benzaldehyde reacts with methanal in presence of NaOH to give benzyl alcohol and sodium methanoate. (B) Propanone reacts with Ba(OH) 2 to form 4-hydroxy- 4-methylpentan-2-one. (C) Iodoform is produced when butanone is treated with NaOI. (D) Carboxylic acids containing α-hydrogen(s) on treatment with Br 2 in presence of red P give α-haloacids. (P) Acidic nature of α-hydrogens (Q) Hydride transfer (R) (S) A B C D (a) Q, R P, Q R, S P, R (b) Q, S P, S P, R, S P, R (c) Q, S P, R, S P, R P, S (d) P, Q Q, R R, S P, S Halogenation Nucleophilic addition Keys are published in this issue. Search now! J No. of questions attempted No. of questions correct Marks scored in percentage …… …… …… Check your score! If your score is > 90% EXCELLENT WORK ! You are well prepared to take the challenge of final exam. 90-75% GOOD WORK ! You can score good in the final exam. 74-60% SATISFACTORY ! You need to score more next time. < 60% NOT SATISFACTORY! Revise thoroughly and strengthen your concepts. CHEMISTRY TODAY | APRIL ‘17 57
CHEMISTRY MUSING SOLUTION SET 44 240× 1000 1. (d) : Bond energy per molecule of I 2 = 6. 022× 10 23 J = 3.985 × 10 –19 J −34 8 Energy absorbed = hc 6. 626× 10 × 3× 10 = λ −10 4500× 10 = 4.417 × 10 –19 J ∴ K.E. of one I 2 molecule = (4.417 × 10 –19 – 3.985 × 10 –19 )J = 4.32 × 10 –20 J 20 432 . × 10 − K.E. of one I atom = = 2.16 × 10 –20 J 2 2. (d) : Nucleophilic addition reaction to carbonyl compound takes place followed by intramolecular nucleophilic substitution reaction. O Cl CH3MgBr, dry ether, 0°C CH 3 Nucleophilic addition reaction MgBrCl + O CH 3 CH 3 aq. acid Cl intra molecular nucleophilic substitution reaction OMgBr CH CH 3 3 3. (b) : The colourless inorganic salt (A) is ammonium nitrate. NH NO NO + 2H O 4 3 2 2 ( A ) ( B ) ( C) Product (B) N 2 O is a neutral gas, product (C) H 2 O is liquid and neutral to litmus. 10N2O + P4 PO 4 10 + 10N2 O 4. (a) : NH O Br 2/KOH (Hoffmann bromamide reaction) (Dehydrating agent) NaOH H HN 2 OOH ONH CH 2 CH 2 COOH -Alanine (II) 5. (d) : Pb 2+ + 2HCl PbCl 2 ↓ HS 2 PbS ↓ + 2HCl White ppt. Black ppt. (dissolves on boiling) r1 6. (c) : Either octahedral voids = 0. 414 or r2 r1 tetrahedral voids = 0. 225 are occupied by r2 [where r 1 is radius of the interstitial site (void) and r 2 is radius of atoms arranged in fcc] interstitial sites in fcc. Since in fcc, atoms along face diagonal are touching, thus, 4r 2 = 2 a Required diameter of interstitial sites = 2r 1 = 2 × 0.414 r 2 = 2 × 0 . 414 × 2 a 4 2× 0. 414× 2 × 400 = 4 = 117.1 pm 7. (b) : SnO 2 + 2NaOH Na 2 SnO 3 + H 2 O 2– SnO 2 + SnO 3 2– [SnO 2 ] ⋮ SnO 3 As they form negatively charged particles, they are easily coagulated by AlCl 3 in which Al 3+ cation carries maximum positive charge. 8. (c) : 50 mL of gold for protection requires = 0.1 g = 100 mg of starch ∴ 10 mL of gold will require = 20 mg of starch ∴ Thus, gold number of starch = 20 9. (5) : We know, p o − p n o = 2 p n1+ n2 Given that: p o = 640 mm Hg, p = 600 mm Hg Let M be the molecular weight of the solute. Molar mass of benzene (C 6 H 6 ) = 6 × 12 + 6 = 78 g mol –1 n . 2 = 175 ; M n 1 = 78 640 − 600 2. 175 / M ∴ = ; M = 65.25 640 2. 175 + 05 . M 60 + x × 1.05 = 65.25 ∴ x = 5 10. (7) : Acidified K 2 Cr 2 O 7 , CuSO 4 , H 2 O 2 , Cl 2 , O 3 , FeCl 3 and HNO 3 oxidise iodide to iodine. Alkaline KMnO 4 oxidises aqueous iodide to IO – 3 ion. Na 2 S 2 O 3 is a strong reducing agent which on reaction with I 2 produces I – ion. 2Na 2 S 2 O 3 + I 2 2NaI + Na 2 S 4 O 6 MPP CLaSS XI ANSWER KEY 1. (c) 2. (b) 3. (a) 4. (d) 5. (d) 6. (c) 7. (c) 8. (d) 9. (a) 10. (c) 11. (b) 12. (c) 13. (c) 14. (c) 15. (c) 16. (d) 17. (a) 18. (d) 19. (d) 20. (a,b,c) 21. (c,d) 22. (a,b,c,d) 23. (b,d) 24. (3) 25. (4) 26. (2) 27. (a) 28. (a) 29. (a) 30. (a) 58 CHEMISTRY TODAY | APRIL ‘17
Page 2 and 3: Volume 26 No. 4 April 2017 Managing
Page 5 and 6: (R) K[Co(NH ) (NO ) 4 ] 1. The volu
Page 7 and 8: 24. m-Bromoaniline can be prepared
Page 9 and 10: (a) (b) (c) (d) CH CH C CH CH CH C
Page 11 and 12: 20. (d) : CH 2 5 alk. KMnO 4 ( A) C
Page 13 and 14: 41. (a) : According to Gibbs’-Hel
Page 15 and 16: 5. Compound 'X' C 7 H 8 O, is insol
Page 17 and 18: (c) (d) O HC 2 O O HC 2 O O CH CH C
Page 19 and 20: 4. As 2 S 3 sol carries a negative
Page 21 and 22: 15. Cl CHONa + EtOH 2 5 Heat Possib
Page 23 and 24: (c) If θ = 10°, the charge underg
Page 25 and 26: (c) (d) NH 2 O heat NH HO 2 C CO 2
Page 27 and 28: (c) Dil. HCl followed by reaction w
Page 29 and 30: 33. Which of the following reaction
Page 31 and 32: Balz-Schiemann reaction : tetrauoro
Page 33 and 34: 26. (c) : HC 3 HC 3 -H O CH 2 3 H +
Page 35 and 36: 12. At equimolar concentration of F
Page 37 and 38: (a) 1s 2 , 2s 2 2p 6 , 3s 2 3p 6 3d
Page 39 and 40: Fraction of M present as M 2+ = 88
Page 41: 26. (b) : According to Gay-Lussac
Page 47 and 48: CONCEPT MAP PERIODICITY IN PROPERTI
Page 49 and 50: Class XII This specially designed c
Page 51: JEE MAIN / JEE ADVANCED / PETs Only
Page 55 and 56: Isothermal reversible expansion :
Page 57 and 58: (a) H 2 O/H + , BH 3·THF/H 2 O 2·
Page 59 and 60: 22. H 2 can be obtained from 28. Th
Page 61 and 62: 7. Predict the product for the foll
Page 63 and 64: 7. (d) : Cyclopropane is under seve
Page 65 and 66: 46. If the first and the (2n - 1) t
Page 67 and 68: 1 (a) 6 2 ms − (b) 4 2 (c) 7 m s
Page 69 and 70: tension, viscous force, weight but
Page 71 and 72: (a) HN 2 SO 3 H (b) (NH 2 ) 2 CO (c
Page 73 and 74: SOLUTIONS PAPER-I 1. (a) : The phot
Page 75 and 76: 11. (a, d) : As, F 1 = k 1 x, F 2 =
Page 77 and 78: Given that, at equilibrium, ⎛ n
Page 79 and 80: 2 ∫ 53. (3) : (| x− 2| + [ x])
Page 81 and 82: percentage change in v = 1 2 perce
Page 83 and 84: Again, c 2 a 2 b 2 = + + 2a⋅b
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