DPP-53 to 54 Physical Chemistry English

DAILY PRACTICE PROBLEMS (DPP) Subject : Physical/Inorg.Chemistry Date : DPP No. 53 to 54 Class : XIII Course : DPP No.53 DPP No.1 Total Marks : 41 Max. Time : 41 min. Single choice Objective ('–1' negative marking) Q.1 to Q.11 (3 marks 3 min.) [33, 33] Subjective Questions ('–1' negative marking) Q.12 to Q.13 (4 marks 4 min.) [8, 8] 1. Which statement about standard reduction potentials is correct (1) E  2 (2) E  = Zero at all temperature = zero at 298 K D / D2 (3) A redox reaction is feasible if sum of SRP of oxidant and that of reductant is a positive quantity (4) K2Cr2O7 (acid) is stronger oxidising agent than KMnO4 (acid) [Given : E – 2 = 1.51 V ; E 2 – 3  = 1.33 V] MnO4 / Mn Cr2O7 / Cr 2. A solution containing NH Cl and NH OH has a hydroxide ion concentration of 10 6 mol lit 1. Which of the 4 4 following hydroxides could be precipitated when this solution is added in equal volume to a solution containing 0.1 M of metal ions. (1) AgOH (Ksp = 5  10 ) (2) Cd(OH) 3 (Ksp = 8  10 6) (3) Mg(OH)2 (Ksp = 3  10 11) (4) Fe(OH) (Ksp = 8  10 16) 3. The solubility products of Al(OH)3 and Zn(OH)2 are 8.5 × 10–23 and 1.8 × 10–14 respectively. If NH OH is added to a solution containing Al3+ and Zn2+ ions, then substance precipitated that is : (1) Al(OH)3 (2) Zn(OH)2 (3) Both together (4) None of these 4. E° for some half cell reactions are given below Sn+4 + 2e–  Sn2+ ; E° = 0.151 v 2Hg2+ + 2e  Hg +2 ; E° = 0.92 v PbO + 4H+ + 2e–  Pb2+ + 2H O ; E° = 1.45 v based on the given data which statement is correct. (1) Sn4+ is a stronger oxidising agent than Pb+4 (2) Sn2+ is a stronger reducing agent than Hg 2+ (3) Hg2+ is a stronger oxidising agent than Pb4+ (4) Pb+2 is a stronger reducing agent than Sn2+ 6. Which of the following equations is not involved in the Solvay process ? (1) CaCO heat  CaO + CO (2) NaCl + NH + H O + CO  NH Cl + NaHCO (3) CaO + 2NH Cl  2NH + H O + CaCl (4) Na CO + CO + H O  2NaHCO 4 3 2 2 2 3 2 2 3 7. The composition of Sorel's cement is : (1) MgCl2 .5H2O (2) MgCl2 .5MgO . nH2O (3) MgCO3 .5H2O (4) MgCO3 .5H2O . nH2O 8. Select the most ionic and most covalent compounds respectively from the following. CrO5, Mn2O7, PbO, P4O10, SnO2 (1) CrO5, Mn2O7 (2) PbO, Mn2O7 (3) CrO5, P4O10 (4) SnO2, CrO5 9. In which of the following sets the central atom of each member involves sp3 hybridisation ? (1) O4– , Cl4– , F4+ (2) XeO3 , XeO4 , XeF4 (3) SO3, SO32– , SO42– (4) PCl4+ , BF4– , ClO4– 10. The BF3 is a planar molecule where as NF3 is pyramidal because : (1) B – F bond is more polar than N – F bond. (2) boron atom is bigger than nitrogen atom. (3) nitrogen is more electronegative than boron. (4) BF3 has no lone pair but NF3 has a lone pair of electrons. 11. Which species has the maximum number of lone pairs of electrons on the central atom? (1) XeOF (2) IF + (3) XeF (4) BrF 4 4 2 3 12.(a) Equal volumes of 0.02 M CaCl2 and 0.0004 M Na2SO4 are mixed . Will a precipitate form . Ksp for CaSO4 = 2.4  10 5 . (b) Will a precipitate form when 0.150 L of 0.10 M Pb(NO3)2 and 0.100 L of 0.20 M NaCl are mixed? K (PbCl ) = 1.2 × 10–5 13. State whether each of the following is true or false. (a) MgCl2 . 6H2O on heating gives anhydrous MgCl2. (b) Aluminium chloride (AlCl3) is a Lewis acid because it can donate electrons. (c) All the Al–Cl bonds in Al2Cl6 are equivalent. (d) Sodium monoxide can be prepared by burning sodium in air. (e) Potassium superoxide is diamagnetic in nature. (f) The thermal stability of hydroxides of group 1 decreases on moving down the group. (g) Potassium carbonate cannot be prepared by Solvay process as potassium bicarbonate is highly soluble in water. (h) All chlorides of Group 1 elements are ionic except LiCl. (i) The metallic oxides of group 1 elements becomes more basic on going down the group. (j) The oxides of alkaline earth metals are more basic then the oxides of alkali metals. (k) The bicarbonates of Mg and Ca are not stable in the crystalline salt. (l) Unlike magnesium chloride, calcium chloride can be obtained by heating CaCl2 . 6H2O. (m) The decrease in the solbuility from BeSO4 to BaSO4 is primarily due to decrease in the hydration energy as one moves from Be2+ to Ba2+. DPP No.54 DPP No.2 Total Marks : 45 Max. Time : 45 min. Single choice Objective ('–1' negative marking) Q.1 to Q.10 (3 marks 3 min.) [33, 33] Multiple choice objective ('–1' negative marking) Q.11 to Q.13 (4 marks 4 min.) [12, 12] 1. The temperature defining the standard electrode potential is (1) 298 K (2) 273 K (3) 373 K (4) any temperature can be selected but it must remain constant and species must be in their standard states. 2. E° for F + 2e– 2F¯ is 2.8 V, E° for ½ F + e– = F¯ is : (1) 2.8 V (2) 1.4 V (3) –2.8 V (4) –1.4 V 3. The standard reduction potential of Cu2+/Cu and Cu2+/Cu+ are 0.337 and 0.153 respectively. The standard electrode potential of Cu+/Cu half-cell is - (1) 0.184 V (2) 0.827 V (3) 0.521 V (4) 0.490 V 4. E0 3  / Fe2 = +0.77 V ; E0  3 / Fe = – 0.036 V. What is E0 2 and is Fe+2 stable to disproportionation in aqueous solution under standard conditions (1) +0.44 V, yes (2) – 0.44 V, No (3) + 0.44 V, No (4) – 0.44 V, yes 5. Given that Eº 2 = – 0.44 V ; Eº 3 2 = 0.77 V if Fe2+, Fe3+ and Fe solid are kept together then Fe Fe Fe Fe (1) Fe3+ increases (2) Fe3+ decreases (3) Fe2+ / Fe3+ remains unchanged (4) Fe2+ decreases 6. 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 7. There is no S–S bond in : (1) S O 2– (2) S O 2– (3) S O 2– (4) S O 2– 8. 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 9. The spontaneous redox reaction/s among the following is/are (1) 2Fe3+ + Fe  3Fe++ (2) Hg ++  Hg++ + Hg (3) 3 AgCl + NO + 2H O  3 Ag + 3 Cl– + NO – + 4H+ Given that  Fe Fe = 0.77 V  Fe Fe = – 0.44 V E  = 0.85 V E   = 0.92 V Hg2 E Hg = 0.22 V Hg E  Hg2 = 0.96 V AgCl Ag NO3 NO (1) a (2) a, b, c (3) a, b (4) a, c 10. G° of the cell reaction AgCl(s) + ½ H (g) Ag(s) + H+ + Cl¯ is –21.52 kJ. G° of 2AgCl(s) + H2(g)  2Ag(s) + 2H+ + 2Cl¯ is : (1) –21.52 kJ (2) –10.76 kJ (3) –43.04 kJ (4) 43.04 kJ 11. Which of the following species are correctly matched with their geometries according to the VSEPR theory? (1) BrF +  octahedral. (2) SnCl –  trigonal bipyramidal. (3) ClF –  linear. (4) IF +  see – saw. 12. For the cell TI | TI+ (0.001 M) | | Cu2+ (0.1 M) | Cu. E at 25°C is 0.83 V, which can be increased- (1) by increasing [Cu2+] (2) by increasing [Tl+] (3) by decreasing [Cu2+] (4) by decreasing [Tl+] 13. The standard reduction potentials of some half cell reactions are given below : PbO + 4H+ + 2e– Pb2+ + 2H O E0 = 1.455 V MnO – + 8H+ + 5e– Mn2+ + 4H O E0 = 1.51 V Ce4+ + e– Ce3+ E0 = 1.61 V H O + 2H+ + 2e– 2H O E0 = 1.71 V Pick out the correct statement : (1) Ce+4 will oxidise Pb2+ to PbO (2) MnO- will oxidise Pb2+ to PbO (3) H2O2 will oxidise Mn+2 to MnO- (4) PbO2 will oxidise Mn+2 to MnO- ANSWER KEY DPP No. 51 1. (4) 2. (2) 3. (2) 4. (1) 5. (2) 6. (2) 7. (2) 8. (3) 9. (1) 10. (3) 11. (a) 1.6 × 10 -5 mol/lit. (b) 2.56 × 10 -9 mol/lit. (c) 1.28 × 10–8 mol/lit. 12. 4 × 10–6 M, 2 × 10–4 M, 50 times. DPP No. 52 1. (2) 2. (1) 3. (2) 4. (4) 5. (1) 6. (4) 7. (2) 8. (2) 9. (4) 10. (1) 11. (1) 12. (a) Will dissolve, 32% saturation (b) will not dissolve, 100% saturation.