DPP-35 to 36 Physical Chemistry

DAILY PRACTICE PROBLEMS (DPP) Subject : Physical/Inorg.Chemistry Date : DPP No. 35 to 36 Class : XIII Course : DPP No.35 DPP No.1 Total Marks : 38 Max. Time : 38 min. Single choice Objective ('–1' negative marking) Q.1 to Q.7 (3 marks 3 min.) [21, 21] Subjective Questions ('–1' negative marking) Q.8 (4 marks 4 min.) [4, 4] BooSt YoUr PreViouS ConCept Single choice Objective ('–1' negative marking) Q.9 to Q.11 (3 marks 3 min.) [9, 9] Multiple choice objective ('–1' negative marking) Q.12 (4 marks 4 min.) [4, 4] 1. The decompostion NH3 gas on a heated tungsten surface gave the following results : Initial pressure (mm) 65 105 y 185 Half-life (sec) 290 x 670 820 Calculate approximately the values of x and y. (1) x = 410 sec (2) x = 467 sec (3) x = 490 sec (4) x = 430 sec y = 115 mm y = 150 mm y = 120 mm y = 105 mm 2. In a first order reaction, the concentrations of the reactant, 30 minutes and 40 minutes after the starts are C1 and C2 (in moles/litre) respectively. What was C0, intial concentration ? C3   C 4  C 3 C4  (1) C0   1    (2) C 0   1  (3) C 0   1  (4) C0   1     2   2   2   2  3. A certain reaction obeys the three-half power law for its order. What function of the concentration may be plotted on the Y-axis against, t on the X-axis to get a linear plot ? 1 (1) C 2 vst (2) 1 vs t C  1 (3) C–2 vs t (4) C 2 vst 4. For the reaction A  C + D, the initial concentration of A is 0.01 M. After 100 sec, the concentration of A is 0.001 M. The rate constant of the reaction has the numerical value of 9.0. What is the unit of the reaction rate constant ? (1) M–1s–1 (2) Ms–1 (3) s–1 (4) M–1.5 s–1 5. The half lives of decomposition of gaseous CH3CHO at constant temperature but at initial pressure of 364 mm and 170 mm Hg were 410 second and 880 second respectively. Hence order of reaction is (1) 2 (2) 3 (3) 1.5 (4) 1 6. The hydrolysis of cane sugar was studied using an optical polarimeter and the following readings were taken: time (min.) : 0 84 min  observed rotation : 50 20 10 (degrees) When was the mixture optically inactive? (log 2 = 0.3, log 3 = 0.48) (1) 118 min (2) 218 min (3) 318 min (4) 418 min 7. Consider the plots for the types of reaction nA  B + C – d [A] dt [A] 1 [A] These plots respectively correspond to the reaction orders : (1) 0, 2, 1 (2) 0, 1, 2 (3) 1, 1, 2, (4) 1, 0, 2 8. Decomposition of N O follows first-order kinetics, 2N O (g) K  4NO (g) + O (g) If pressure of the system 2 5 2 5 2 2 at time, t and  are Pt and P respectively, find the expression of rate contant (k). BooSt YoUr PreViouS ConCept 9. In which of the following arrangements, the sequence is not strictly according to the property written against it? (1) HF < HCl < HBr < HI : increasing acid strength (2) NH3 < PH3 < AsH3 < SbH3 : increasing basic strength (3) B < C < O < N : increasing first ionization enthalpy (4) CO2 < SiO2 < SnO2 < PbO2 : increasing oxidising power 10. Which of the following statements is wrong ? (1) Metals are more than non-metals (2) There are only few metalloids (3) Hydrogen can be placed with alkali metals as well as with halogen in periodic table (4) Non metals are more than metals 11. The set representing the correct order of ionic radius is : (1) Na+ > Li+ > Mg2+ > Be2+ (2) Li+ > Na+ > Mg2+ > Be2+ (3) Mg2+ > Be2+ > Li+ > Na+ (4) Li+ > Be2+ > Na+ > Mg2+ 12. Which of the following statement is/are correct ? (1) The first ionisation energies (in kJ mol–1) of carbon, silicon, germanium, tin, and lead are 1086, 786, 761, 708 and 715 respectively : (2) Down the group, electronegativity decreases from B to Tl in boron family. (3) Among oxides of the elements of carbon family, CO is neutral, GeO is acidic and SnO is amphoteric. (4) The 4f-and 5f-inner transition elements are placed separately at the bottom of the periodic table to maintain its structure. DPP No.36 DPP No.2 Total Marks : 39 Max. Time : 39 min. Single choice Objective ('–1' negative marking) Q.1 (3 marks 3 min.) [3, 3] Multiple choice objective ('–1' negative marking) Q.2 (4 marks 4 min.) [4, 4] Subjective Questions ('–1' negative marking) Q.3 to Q.7 (4 marks 4 min.) [20, 20] BooSt YoUr PreViouS ConCept Single choice Objective ('–1' negative marking) Q.8 to Q.11 (3 marks 3 min.) [12, 12] 1. Rate constant k = 2.303 min–1 for a particular reaction. The initial concentration of the reaction is 1 mol/litre then rate of reaction after 1 minute is : (1) 2.303 M min–1 (2) 0.2303 M min–1 (3) 0.1 M min–1 (4) none of these 2. For a certain reaction A  2 Which of the following is true : products, the t½ as a function of [A]0 is given as below : (1) The order is 1 (2) t 2 ½ would be 100 10 min for [A]0 = 1 M (3) The order is 1 (4) t½ would be 100 min for [A]0 = 1 M 3. Let there be as first-order reaction of the type, A  B + C. Let us assume that all the three species are gases. We are required to calculate the value of rate constant based on the following data. Time 0 T  Partial pressure of A P0 Pt – 4. Let there be a first order reaction, A  B + C. Let us assume all there are gases. We are required to calculate the value of rate constant based on the following data Time 0 t  Total pressure P0 Pt – Calculate the expression of rate constant. 5. A(g)  B(g) + C(g) Calculate the expression of rate constant. 6. The plot of log (V – V) versus t (where V is the volume of nitrogen collected under constant temperature and pressure conditions) for the decomposition of C6H5N2Cl is given at 50°C with an amount of C6H5N2Cl equivalent to 58.3 cc N2. 1.75 log(V – V) 1.0 5 10 15 20 25 30 time(min.) Calculate the rate constant for the reaction in hr–1 expressing your answer in a single significant digit. 7. For the reaction, 2NO + H  N O + H O the value of -dp/dt was found to be 1.50 Torr s–1 for a pressure 2 2 2 of 359 Torr of NO and 0.25 Torr s-1 for a pressure of 152 Torr, the pressure of H being constant. On the other hand, when the pressure of NO was kept constant, –dp/dt was 1.60 Torr s–1 for a hydrogen pressure of 289 Torr and 0.79 Torr s–1 for a pressure of 147 Torr. Determine the order of the reaction. BooSt YoUr PreViouS ConCept 8. Which is not true about B2H6 (1) Both ‘B’ atoms are sp3 hybridised (2) Boron atom is in ground state (3) Two hydrogens occupy special positions (4) There are two, three centre two electron bonds 9. In P4 O10 molecule (1) There are 4 P–P bond (2) There are 8 P–O bond ^ (3) The P OP bond angle is 180° (4) The phosphorus atom is in excited state 10. Consider the following statements In    v CH2  CH C  C H 1. There are 6  and ‘3’  and 2. Carbon  &  are sp2 hybridised 3. Carbon  & V are sp hybridised, The above statements 1, 2, 3 respectively are (T = True, F = False) (1) T T T (2) F T T (3) F T F (4) T F T 11. Consider the following statements S1 : Steric number ‘7’ gives ‘sp3d3 hybridisation. S2 : In C𝑙F3 at least one bond angle is exactly 180° S3 : Lone pair does not cause any distortion in the bond angle. S4 : Correct order of dipole moment NF3 > NH3 > CO2 (1) T F F T (2) T F F F (3) T T F F (4) T T F T ANSWER KEY DPP No.-33 1. 4 2. 3 3. 4 4. 4 5. 3 6. 4 7. 4 8. 2 9. 2, 4 DPP No.-34 1. 4 2. 2 3. 3 4. 1 5. 3 6. 3 7. 4 8. 1 9. 1, 2, 3

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