DPP-55 to 56 Physical Chemistry English

DAILY PRACTICE PROBLEMS (DPP) Subject : Physical/Inorg.Chemistry Date : DPP No. 55 to 56 Class : XIII Course : DPP No.55 DPP No.1 Total Marks : 39 Max. Time : 39 min. Single choice Objective (no negative marking) Q.1 to Q.9 (3 Marks, 3 Min.) [27, 27] Multiple choice objective (no negative marking) Q.10 (4 marks 4 min.) [4, 4] Subjective Questions (no negative marking) Q.11 to Q.12 (4 marks 4 min.) [8, 8] 1. Which of the following concentration cells will produce maximum Ecell at 298 K. [Take pH = 1.0 atm in each case.] (1) Pt | H (g) | H+ (0.01 M) || H+ (0.1 M) | H (g) | Pt (2) Pt | H (g) | NH Cl (0.01 M) || HCl (0.1 M) | H (g) | Pt 2 2 2 4 2 (3) Pt | H (g) | H+ (0.1 M) || H+ (0.2 M) | H (g) | Pt (4) Pt | H (g) | H+ (pH = 0.0) || H+ (pH = 0.0) | H (g) | Pt. 2 2 2 2 2. Given that (at T = 298 K) Cu(s) | Cu2+ (1.0 M) || Ag+ (1.0 M) | Ag(s) Eº = 0.46 V Zn(s) | Zn2+ (1.0 M) || Cu2+ (1.0 M) | Cu(s) cell Eºcell = 1.10 V Then Ecell for, Zn | Zn (0.1 M) || Ag (1.0 M) | Ag at 298 K will be : 2+ + (1) 1.59 V (2) 1.53 V (3) 2.53 V (4) cannot be calculated due to insufficient data 3. What is the value of the reaction quotient, Q, for the cell, Ni(s) | Ni(NO3)2 (0.190M) | | KCl(0.40M)| Cl2(g, 0.10 atm) |Pt(s) (1) 3 x 10–1 (2) 1.3 x 10–1 (3) 8.0 x 10–2 (4) 3.0 x 10–2 4. For the cell Pt | H2(g) | solution X || KCl (saturated) | Hg2 Cl2 | Hg | Pt the observed EMF at 25°C was 600 mV. When solution X was replaced by a standard phosphate buffer with pH = 7.00, the EMF was 718 mV. Find the pH of solution X. (1) 3 (2) 4 (3) 5 (4) 6 5. The dissociation constant for [Ag(NH ) ]+ into Ag+ and NH is 10–13 at 298 K. If E0  = 0.8 V, then E0 for 3 2 3 the half cell [Ag(NH ) ]+ + e–  Ag + 2NH will be : Ag Ag (1) 0.33 V (2) – 0.33 V (3) – 0.033 V (4) 0.033 V 6. You are given the following cell at 298 K with Eºcell = 1.10 V Zn(s) | Zn2+ (C ) || Cu++ (C ) | Cu(s) 1 2 where C1 and C2 are the concentration in mol/lit then which of the following figures correctly correlates Ecell as C1 a function of concentrations. x-axis : log C2 and y-axis : Ecell (1) (2) (3) (4) 7.(a) Which process occurs in the electrolysis of an aqueous tin(II) chloride solution at a tin anode? (1) Sn = Sn2+ + 2e– (2) 2Cl- = Cl + 2e– (3) 2H O = O + 4H+ + 4e– (4) none of these 7.(b) In the electrolysis of an aqueous nickel(II) sulphate solution, the process 2H2O = 2O2 + 4H + 4e occurs at + - the anode. The material of construction of the anode is : (1) nickel (2) gold (3) copper (4) none of these 8. In the electrolysis of an aqueous solution of a salt, the pH in the space near one of the electrodes increased. A solution of which salt is being electrolyzed? (1) none of the following (2) CuCl2 (3) Cu(NO3)2 (4) KCl 9. Number of electrons lost during electrolysis of 0.355 g of Cl¯ is : 0.01 (1) 0.01 (2) 0.01 NA (3) 0.02 NA (4) 2NA 10. Make out the right combination of cell and condition for the spontaneity : (1) Pt (H2) | HCl | Pt (H2) ; P1 > P2 (2) Zn | Zn2+ (C ) || Zn2+ (C ) | Zn ; C > C P1 1M P2 (3) Pt (Cl ) | Cl– (C ) || Cl– (C ) | Pt (Cl ) ; C > C (4) Pt (H ) | HCl (C ) || HCl (C ) | Pt (H ) ; C > C 2 1 2 2 2 1 2 1 2 2 2 1 1 atm 1 atm 1 atm 1 atm 11. Calculate E° and E for the cell Sn | Sn2+ (1M) || Pb2+ (10–3 M) | Pb , E° (Sn2+ / Sn) = – 0.14V. Eº (Pb2+ / Pb) – 0.13V. What do you infer from cell EMF? 12. At 25°C the value of K for the equilibrium Fe3+ +Ag Fe2+ + Ag+ is 0.5 mol/litre. The standard electrode potential for Ag+ + e Ag is 0.8 V. What is the standard potential for Fe3+ + e Fe2+ ? DPP No.56 DPP No.2 Total Marks : 33 Max. Time : 33 min. Single choice Objective (no negative marking) Q.1 to Q.6 (3 Marks, 3 Min.) [18, 18] BooSt YoUr PreViouS ConCept Single choice Objective (no negative marking) Q.7 to Q.11 (3 Marks, 3 Min.) [15, 15] 1. pH of the solution in the anode compartment of the following cell at 25ºC is x when Ecell – Eºcell = 0.0591 V, Pt(H ) (1 atm) | pH = x | | Ni2+ (1 M) | Ni x is : (1) 4 (2) 3 (3) 2 (4) 1 2. In the electrolysis of a copper(II) chloride solution, the mass of the cathode increased by 3.2 g. What occurred at the copper anode? (1) 0.05 mol of Cu2+ passed into the solution (2) 0.56 L of O was liberated (3) 0.1 mol of Cu2+ passed into the solution (4) 0.112 L of Cl was liberated 3. The passage of a constant current through a solution of dilute H2SO4 with ‘Pt’ electrodes liberated 336 cm3 of a mixture of H2 and O2 at S.T.P. The quantity of electricity that was passed is : 1 (1) 96500 C (2) 965 C (3) 1930 C (4) 100 faraday 4. A very thin copper plate is electro-plated with gold using gold chloride (AuCl3) in HCl. The current was passed for 20 min. and the increase in the weight of the plate was found to be 2g. The current passed was : [Au = 197, Cl = 35.5]. (1) 0.816 amp (2) 1.632 amp (3) 2.448 amp (4) 3.264 amp 5. What must be the concentration of Ag+ in an aqueous solution containing Cu2+ = 1.0 M so that both the metals can be deposited on the cathode simultaneously. Given that 0 Cu Cu 2  = – 0.34 V and Ag Ag = 0.812 V, T = 298 K (1) nearly 10–19 M (2) 10–12 M (3) 10–8 M (4) nearly 10–16 M 6. Electrolytic reduction of 6.15 g of nitrobenzene into aniline using a current effeciency of 40% will require which of the following quantity of electricity. [C = 12, H = 1, N = 14, O = 16] (1) 0.75 F (2) 0.15 F (3) 0.75 C (4) 0.125 C BooSt YoUr PreViouS ConCept 7. Magnesium cation has plarisation power close to that of : (1) Li+ (2) Na+ (3) K+ (4) Cs+ 8. Which of the following compound is form when the products of electrolysis of brine solution at anode and cathode are made to contact : (1) NaCl (2) H2 (3) NaOCl (4) Cl2 9. When dry ammonia gas is passed over heated sodium (in absence of air) the product formed is : (1) sodium hydride (2) sodium nitride (3) sodamide (4) sodium cyanamide 10. At high temperature, nitrogen combines with CaC2 to give : (1) calcium cyanide (2) calcium cyanamide (3) calcium carbonate (4) calcium nitride 11. Which of the following compounds does not have similarity in their structural aspect ? (1) FeSO4. 7H2O (2) Na2CO3 . 7H2O (3) MgSO4. 7H2O (4) ZnSO4 . 7H2O ANSWER KEY DPP No.-53 1. 1 2. 4 3. 1 4. 2 6. 4 7. 2 8. 2 9. 4 10. 4 11. 3 12. (a) No. ; (b) Yes 13. (a) F (b) F (c) F (d) F (e) F (f) F (g) T (h) T (i) T (j) F (k) T (l) T (m) T DPP No.-54 1. 4 2. 1 3. 3 4. 1 5. 2 6. 4 7. 4 8. 1 9. 1 10. 3 11. 1,2,3,4 12. 1, 4 13. 1, 2, 3

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