DPP-37 to 38 PC English Physical Chemistry

DAILY PRACTICE PROBLEMS (DPP) Subject : Physical/Inorg.Chemistry Date : DPP No. 37 to 38 Class : XIII Course : DPP No.37 DPP No.1 Total Marks : 29 Max. Time : 29 min. Single choice Objective ('–1' negative marking) Q.1 to Q.9 (3 marks 3 min.) [21, 21] Multiple choice objective ('–1' negative marking) Q.10 (4 marks 4 min.) [4, 4] Subjective Questions ('–1' negative marking) Q.11 (4 marks 4 min.) [4, 4] 1. The reaction A(g) + 2B(g)  C(g) is an elementary reaction. In an experiment involving this reaction, the initial partial pressures of A and B are PA = 0.40 atm and PB = 1.0 atm respectively. When pressure of C becomes 0.3 atm in the reaction the rate of the reaction relative to the initial rate is : 1 (1) 12 1 (2) 50 1 (3) 25 (4) none of these 2. A reaction is catalysed by H+ ion;and in the rate law the dependence of rate is of first order with respect to the concentration of H+ ions, in presence of HA rate constant is 2 × 10–3 min–1 and in presence of HB rate constant is 1 × 10–3 min–1. HA and HB (both strong acids) have relative strength as : (1) 0.5 (2) 0.002 (3) 0.001 (4) 2 3. The gaseous decomposition reaction, A(g)  2B(g) + C(g) is observed to first order over the excess of liquid water at 25ºC. It is found that after 10 minutes the total pressure of system is 188 torr and after very long time it is 388 torr. The rate constant of the reaction (in hr–1) is : [Given : vapour pressure of H O at 25º is 28 torr (ln 2 = 0.7, ln 3 = 1.1, ln 10 = 2.3)] (1) 0.02 (2) 1.2 (3) 0.2 (4) none of these. 4. For a certain reaction the variation of the rate constant with temperature is given by the equation ln kt = ln k0 + 0.0693 t (t  0°C) The value of the temperature coefficient of the reaction rate is therefore (1) 0.1 (2) 1.0 (3) 10 (4) 2 5. What percentage fraction of the molecule will cross over the energy barrier at 1000 K temperature for 18.424 KJ activation energy (R = 8J mol –1 K–1) (1) 10% (2) 20% (3) 90% (4) 80% 6. For the decomposition of H the following logarithmic plot is shown : [R = 1.98 cal/mol-K] The activation energy of the reaction is about (1) 45600 cal (2) 13500 cal (3) 24600 cal (4) 32300 cal 7. Decomposition of A follows first order kinetics by the following equation. 4A(g)  B(g) + 2C(g) If initially, total pressure was 800 mm of Hg and after 10 minutes it is found to be 650 mm of Hg. What is half- life of A ? (Assume only A is present initially) (1) 10 mins (2) 5 mins (3) 7.5 mins (4) 15 mins 8. For 2A B + 3C, 2C k2  3D, assuming all reactions to be single step (Elementary) reactions, which of the following is correct : (1) d[C] / dt = 3k1 [A]2 – 3 k–1 [B] [C]3 – 2k2 [C]2 (2) d[B] / dt = k1 [A]2 (3) d[A] / dt = 2k–1 [B] [C]3 – 2k1 [B] [C]3 (4) None 9. For the follwing parallel chain reaction if the sum of the concentration of B and C at any time is 2M then what will be [B] t and [C] t respectively? 11 13 3 5 4 6 8 18 (1) 12 M 12 M (2) M, M 4 4 (3) 5 M, 5 M (4) 13 M, 13 M 10. For the reaction CH4 + Br2  CH3Br + HBr the experimental data require the following rate equation : d k1[CH4 ][Br2 ] dt [CH3Br] = 1 k 2[HBr] /[Br2 ] Which of the following is/are true regarding this ? (1) The reaction is a single step reaction (2) The reaction is 2nd order in the initial stages {[HBr]  0} (3) The reaction is 2nd order in the final stages {[Br2]  0} (4) The molecularity of the reaction is two. 11. For the reaction Cl2 + CO  Cl CO the rate law is d [Cl2CO] dt = k [Cl ]3/2 [CO] The mechanism which is accepted is Cl2 + M 2Cl + M (fast) Cl + CO + M ClCO + M (fast) ClCO + Cl2 Cl2CO + Cl (slow) Find the expression relating k with the other constants given. DPP No.38 DPP No.2 Total Marks : 43 Max. Time : 43 min. Single choice Objective ('–1' negative marking) Q.1 to Q.6 (3 marks 3 min.) [18, 18] Multiple choice objective ('–1' negative marking) Q.7 (4 marks 4 min.) [4, 4] Subjective Questions ('–1' negative marking) Q.8 to Q.9 (4 marks 4 min.) [8, 8] BooSt YoUr PreViouS ConCept Single choice Objective ('–1' negative marking) Q.10 to Q.12 (3 marks 3 min.) [9, 9] Multiple choice objective ('–1' negative marking) Q.13 (4 marks 4 min.) [4, 4] 1. Select the incorrect statement : (1) Larger the value of Ea , smaller the value of rate constant (k). (2) Larger the value of Ea , greater is the effect on the value of k for a given temperature change. (3) At lower temperature, increase in temperature cause more change in the value of k than at higher temperature. (4) k is affected by change in concentration. 2. The IUPAC name for the complex compound Li[AlH4] is : (1) lithium aluminium hydride (2) hydrido - aluminiumlithium () (3) lithium tetrahydridoaluminate () (4) lithium tetrahydridoaluminate () 3. The IUPAC name for K [CrVINH (CN) O (O )] is 2 3 2 2 2 (1) potassium amminedicyanido-C-dioxidoperoxidochromate(V) (2) potassium amminedicyanatotetraoxochromium() (3) potassium amminedicyanochromate (V) (4) potassium amminocyanodiperoxochromate (V) 4. The IUPAC name for K2 [OsCl5N] is (1) potassium pentachloroazidoosmate (VIII) (2) potassium pentachloroazoosmate (V) (3) potassium pentachloridonitridoosmate (V) (4) potassium nitroosmate () 5. The formula of the complex sodium hydridotrimethoxoborate () is : (1) Na4 [B4H2(OCH3)3] (2) Na2 [BH(OCH3)3] (3) Na [BH2(OCH3)3] (4) Na [BH (OCH3)3] 6. For the reaction 2NO + Br2  2NOBr, the following mechanism has been given NO + Br2 NOBr2 NOBr + NO slow  2NOBr. Hence, rate law is : (1) k[NO]2[Br ] (2) k[NO][Br ] (3) k[NOBr ][NO] (4) k[NO][Br ]2 2 2 2 2 7. In the following gaseous phase first order reaction A(g)  2B(g) + C(g) initial pressure was found to be 400 mm and it changed to 1000 mm after 20 min. Then : (1) Half life for A is 10 min (2) Rate constant is 0.0693 min–1 (3) Partial pressure of C at 30 min is 350 mm (4) Total pressure after 30 min is 1100 mm 8. Write IUPAC names of the following (a) [Co(NH3)6][CuCl5] (b) [V(H2O)6]Cl3 (c) (NH4)3[Co(C2O4)3] (d) Cl4 (e) (f) Na2[SiF6] (g) K2 [CrO4] (h) [(NH3)5Cr – OH – Cr(NH3)5]Cl5 (i) [Fe(en)3] [Fe(CO)4] (j) [TiCl4(Et2O)2] (k) Mn2(CO)10 (l) [VO(acac)2] (m) Fe4 [Fe(CN)6]3 9. Write the structure formula corresponding to each of the following IUPAC names : (a) hexaamminechromium (III) tetrachloridocuprate (II) (b) diamminedichloridoplatinum (II) (c) tetracarbonyl nickel(0) (d) tetraammineplatinum(II) amminetrichloridoplatinate (II) (e) sodium dithiosulphatoargentate(I) (f) potassium tetracyanido-C-nickelate(0) (g) bis( 5  cyclopentadienyl)iron (II) (h) tetrathiocyanato-N-zincate (II) ion (i) potassium tetraoxidomanganate(VII) (j) potassium trioxalatoaluminate (III) (k) tetrapyridineplatinum (II) tetrachloridoplatinate (II) BooSt YoUr PreViouS ConCept 10. Which of the following are isoelectronic and isostructural ? (1) NO +, CO (2) NO –, BF (3) NH , CH – (4) all of these. 2 2 3 3 3 3 11. There is no S–S bond in : (1) S O 2– (2) S O 2– (3) S O 2– (4) S O 2– 12. What is the correct order from the weakest to the strongest carbon-oxygen bond for the following species ? CO, CO , CO 2– , CH OH. 2 3 3 (1) CH OH < CO 2– < CO < CO (2) CO < CO < CO 2– < CH OH (3) CH OH < CO 2– < CO < CO (4) CH OH < CO < CO 2– CO 13. Which of the following species are correctly matched with their geometries according to the VSEPR theory? (1) BrF +  octahedral. (2) SnCl –  trigonal bipyramidal. 6 5 (3) ClF –  linear. (4) IF +  see – saw. 2 4 ANSWER KEY DPP No. 35 1. 2 2. 4 3. 4 4. 1 5. 1 6. 2 7. 4 1  3P  ln 2K 5(P   P ) 9. 2 10. 4 11. 1 12. 1, 3, 4   t  DPP No. 36 1. 2 2. 1, 2 3. k =  t  n  0 t  t 6. 4 hr–1 7. 3 8. 2 9. 4 10. 2 11. 2

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