Chemistry-5.Open Test-Paper-2

CHEMISTRY Test-Paper-2) MULTIPLE CHOICE QUESTIONS (MULTIPLE OPTIONS CORRECT) 18. Which of the following statement is/are true? (A) Alkali metals are soft metals and softness increases down the group (B) Lattice energy of alkali metal salts with same anion decreases with increase in size of cations (C) Paramagnetic character of Na-Liq NH3 solution decreases in increase in the conc. of NH3 (D) LiF has lowest solubility among all alkali metal halides 19. Which of the following compound are unstable towards heat? (A) Ca(OH)2 (B) NaHCO3 (C) MgCO3 (D) Na2CO3 20. The solubility of alkaline earth metal salts in water decreases down the group, the salts are (A) phosphates (B) sulphates (C) carbonates (D) hydroxides 21. In the extraction of Li, a mixture of dry lithium chloride and potassium chloride is fused and electrolysed, the following fact(s) is/are correct regarding this (A) KCl increases the conductivity (B) M.P. of LiCl lowers due to presence of KCl (C) Reduction potential of Li+ is higher than K+ in fused state (D) Reduction potential of Li+ is lower than K+ in fused state 22. Which of the following ions leads to hardness of water? (A) Mg2+ (B) (C) Ca2+ (D) OH− 23. Which of the following ion is most stable in aq. solution? (A) (B) H2F+ (C) H2O+ (D) 24. Which of the following is/are not a characteristic of effusion? (A) The rate of effusion is inversely proportional to average speed of the gas particles (B) Gases mix as a result of the random motion and frequent collision of gas particles (C) The rate of effusion decreases with increasing temperature (D) Rate of effusion is directly proportional to molar mass of the gas 25. Which of the following is/are characteristic of a tetrahedral complex? (A) the and orbitals are the low energy orbitals (B) most tetrahedral complex are high spin (C) crystal filed splitting is about twice found in octahedral complexes (D) the splitting pattern is just opposite of that in octahedral complexes 26. What are the possible oxidation state(s) of the Cr in the complex K2[Cr(NO)(NH3)(CN)4]. Given (magnetic moment)  = 1.73 BM. (A) +2 (B) +3 (C) +1 (D) All are possible NUMERICAL BASED QUESTIONS 27. One mole of an ideal gas is expanded isothermally at 298 K until its volume is tripled. Find the value of (entropy of system) if the expansion is a free expansion (in vacuum). Given (log3= 0.477 R = 8.3 JK−1mol−1). Give your answer in JK−1 upto two decimals only. 28. The covalent bond energy of C−C bond is 346 kJmol−1 in diamond. Calculate the enthalpy of dissociation (or atomization) per mole for diamond. (Give your answer in kJmol−1.) 29. Sodium hypochlorite reacts with ammonia to provide NH2Cl in basic solution Initial rate data for this reaction are obtained pH Initial [OCl−] Initial [NH3] Initial rate (m/s) 12 0.001 0.01 0.010 The following mechanism has been proposed for this reaction fast equilibrium constant (Keq) slow, rate constant K2 First step is in equilibrium and the second step is rate determining. Calculate the value of rate constant K2 for the second step. Given Ka for HOCl is 10−8. (Give your answer in logK2.) 30. Gold metal is extracted from its ore by treating the crushed rock with an aerated cyanide solution. The unbalanced equation for the reaction is Use any of the following data at 27oC to calculate for this reaction in basic solution. Given Kf for Use equation and R = 8 Jmol−1K−1, F = 96500 C. Give your answer (mode only) in kJ. MATCH THE FOLLOWING QUESTIONS 31. Devise a series of reactions to convert ethyl-3-oxobutanoate to (A), (B), (C) and (D). Select reagents and conditions from the following table: (1) Sodium ethoxide in ethanol (2) Ethanol + acid catalyst and heat (3) H3O+, heat (4) CO2 then H3O+ (5) Mg in ether (6) PBr3 (7) NaBH4 in alcohol (8) CH2I2 in alcohol (9) BrCH2CO2C2H5 (10) (CH3CO)2O + Pyridine List – I List – II (A) To ethyl-4-oxopentanoate (i) (3) then (7) then (6) then (5) then (9) then (3) (B) To 2-bromopropane (ii) (1) then (9) then (3) then (2) (C) To 2-methyl cyclopropyl carboxylic acid (iii) (3) then (7) then (6) (D) To 3-methyl butanoic acid (iv) (7) then (3) then (8) 32. Match the List – I with the List – II. List – I List – II (A) True statement for stereoisomers of C6H6Cl6 (Gamaxene) (i) 8 stereo isomers (B) (ii) 2 optically active isomers (C) (iii) A meso compound (D) (iv) Compound does not have any chiral centre and optically inactive (v) 4 optically active isomers (vi) 2 optically active and one meso compound 33. Match the product of following reactions. List – I List – II (A) (i) N2 (B) (ii) CO2 (C) (iii) H2O (D) (iv) NH3 (v) CaC2 (vi) CaCO3 (vii) N3H (viii)Ca(OH)2 (ix) CaCl2 34. Match List – I with List – II. List – I List – II (A) A blue solution (i) Cu(OH)2 (B) A blue precipitate (ii) CuSO4.5H2O (C) Red colour compound (iii) [Co(SCN)4]2− (D) Tetra coordinated compound (iv) KFe[Fe(CN)6] (v) [Ni(NH3)6] (OH)2 (vi) Pb3O4 (vii) HgI2 ANSWERS 18. A,B,C,D 19. A,B,C 20. A,B,C 21. A,B,C 22. A, C 23. A 24. A, B, C, D 25. A, B, D 26. C 27. 9.11 28. 692 29. 7 30. 345 31. A – (ii) B – (iii) C − (iv) D – (i) 32. A – (i), (ii) B – (iv) C − (ii) D – (v) 33. A – (i), (ii), (iii) B – (iv), (vi) C − (i), (iii), (ix) D – (iii), (vii) 34. A – (ii, iii, v) B – (I, iv) C − (vi, vii) D – (ii, iii) HINTS & SOLUTIONS 27. = 1  8.3  298  2.303  0.477 = 2717.67 J 29. Rate = K2[HOCl][NH3] 0.01 = K2  10−7  0.01 K2 = 107 log K2 = 7 30. Balance eq. is (i) (ii) 31. (A) (B) (C) (D)