Questions for discussion
The emf of a Daniel cell at 298 K is E
Download 230.37 Kb.
|
70. The emf of a Daniel cell at 298 K is E1  when the concentration of ZnSO4 is 1.0 M and that of CuSO4 is 0.01 M, the emf changed to E2. What is the relationship between E1 and E2?
a) E1 = E2 b) E2 = 0 ≠ E1 c) E1 > E2 d) E1 < E2 71. The standard emf of a galvanic cell involving cell reaction with n = 2 is found to be 0.295 V at 250C. The equilibrium constant of the reaction would be: a) 2.0 1011 b) 4.0 1012 c) 1.0 102 d) 1.0 1010 72. If  = –0.441 V and  = 0.771 V, the standard emf of the reaction: Fe + 2Fe3+ → 3Fe2+ will be:
a) 0.330 V b) 1.653 V c) 1.212 V d) 0.111 V 73. A hypothetical electrochemical cell is : A|A+(xM) || B+(yM) | B. The emf measured is +0.20 V. Cell reaction is: a) A+ + B → A + B+ b) A+ + e– → A; B+ + e– → B c) can't be predicted d) A + B+ → A+ + B 74. On the basis of the following E0 values, the strongest oxidizing agent is [Fe(CN)6]4– → [Fe(CN)6]3–] + e–; E0 = – 0.35 V Fe2+ → Fe3+ + e– ; E0 = – 0.77 V a) [Fe(CN)6]4– b) Fe2+ c) Fe3+ d) [Fe(CN)6]3– 75. The equilibrium constant of : Cu(s) + 2Ag+(aq) → Cu2+(aq) + 2Ag(s); E0 = 0.46 V at 298 K is: a) 2.4 × 1010 b) 2.0 × 1010 c) 4.0 × 1010 d) 4.0 × 1015 76. Kohlrausch’s law states that at a) finite dilution, each ion makes definite contribution to equivalent conductance of an electrolyte, whatever be the nature of the other ion of the electrolyte b) infinite dilution, each ion makes definite contribution to equivalent conductance of an electrolyte depending on the nature of the other ion of the electrolyte. c) infinite dilution, each ion makes definite contribution to conductance of an electrolyte whatever be the nature of the other ion of the electrolyte. d) infinite dilution, each ion makes definite contribution to equivalent conductance of an electrolyte, whatever be the nature of the other ion of the electrolyte.
a) 1.968 V b) 2.0968 V c) 1.0968 V d) 0.0968 V 78.Which of the following contains ionic, covalent and co-ordinate bonds? a) NaOH b) NaCl c) NaCN d) NaNC 79.The approximate time duration in hours to electroplate 30 g of calcium from molten calcium chlride using a current of 5 amp is [At. mass of Ca = 40] a) 8 b) 80 c) 10 d) 16 80.5 mL of 0.4 N NaOH is mixed with 20 mL of 0.1 N HCl. The pH of the resulting solution will be a) 6 (b) 7 c) 8 d) 5 81.On adding which of the following, the pH of 20 mL of 0.1 N HCl will not alter? [CET 2012] a) 1 mL of 1N HCl b) 20 mL of distilled water c) 1 mL of 0.1 N NaOH d) 500 mL of HCl of pH = 1 82.Which one of the following has a potential more than zero? a) Pt, 1/2H2(1 atm)| HCl(1M) b) Pt, 1/2 H2(1 atm)| HCl(2M) c) Pt, 1/2H2(1 atm)| HCl(0.1M) d) Pt, 1/2 H2(1 atm)| HCl(0.5M) 83.The standard reduction potentials for Zn2+/Zn, Ni2+/Ni, and Fe2+/Fe are −0.76, −0.23 and −0.44 V respectively. The reaction X + Y2+ → X2+ + Y will be spontaneous when a) X = Ni, Y = Fe b) X = Ni, Y = Zn c) X = Fe, Y = Zn d) X = Zn, Y = Ni 84.Iron exhibits +2 and +3 oxidation states. Which statements about iron is incorrect? a) Ferrous oxide is more basic in nature than the ferric oxide b) Ferrous compounds are relatively more ionic than the corresponding ferric compounds c) Ferrous compounds are less volatile than the corresponding ferric compounds d) Ferrous compounds are more easily hydrolysed than the corresponding ferric compounds
a) F2 and I− b) Br2 and Cl− c) Cl2 and Br− d) Cl2 and I2 86.Molar conductivities  at infinite dilution of NaCl, HCl and CH3COONa are 126.4, 425.9 and 91.0 S cm2 mol−1 respectively. for CH3COOH will be
a) 425.5 S cm2 mol−1 b) 180.5 S cm2 mol−1 c) 290.8 S cm2 mol−1 d) 390.5 S cm2 mol−1 87.Four successive members of the first series of the transition metals are listed below. For which one of them the standard potential  value has a positive sign?
a) Co(Z = 27) b) Ni(Z = 28) c) Cu(Z = 29) d) Fe(Z = 26) 88.The Gibb’s energy for the decomposition of Al2O3 at 5000C is as follows  , ΔrG= + 960 kJ mol−1 The potential difference needed for the electrolytic reduction of aluminium oxide (Al2O3) at 5000C is at least
a) 4.5 V b) 3.0 V c) 2.5 V d) 5.0 89. The quantity of charge required to deposit one gram equivalent of a bi-valent metal is a) 193000 C b) 289500 C c) 48250 C d) 96500 C 90. Faraday constant value is obtained by taking the a) ratio of Avagadro num ber & Electron charge b) product of Avagadro number & Valency of ion c) ratio of Avagadro number & Valency of ion d) product of Avagadro number & Electron charge
1) the resistance increases with increasing temperature (2) the resistance decreases with increasing temperature 3) the flow of current does not generate heat 4) the resistance is independent of the length of conductor
1) their molecules contain unpaired electrons which are mobile 2) their molecules contain loosely held electrons, which get free under the influence of voltage 3) the molecules break up into ions when a voltage is applied (4) molecules will have broken up into ions when electrolyte is fused or is dissolved in the solvent
1) only in solution 2) only in the fused state (3) both in solution in the fused state 4) conducts electricity in dissolved state both in fused state
1) metallic compounds 2) carbon compounds (3) electrovalent compounds 4) covalent compounds 95. When a solution of an electrolyte is heated, the conductance of the solution 1) decreases because increased thermal agitation of solvent molecules affers resistance to the movement of ions 2) increases because the electrodes conduct better 3) decreases because the dissociation of the electrolyte is suppressed (4) increase because the electrolyte is dissociated more
1) 0.1 M NaCl (2) 0.1 M Na2SO4 3) 0.1 M HCN 4) 0.1 M HCN 97. Which of the following is a weak electrolyte? 1) Ammonium acetate 2) Ammonium carbonate (3) Ammonium hydroxide 4) Ammonium citrate 98. Which of the following statements does not apply for weak electrolytes? 1) conductivity of weak electrolytes at moderate concentration is extremely poor 2) law of chemical equilibrium can be applied to the dissociation of weak electrolytes 3) dissociation constant for weak electrolyte is very low (4) degree of dissociation of weak electrolyte is appreciably high a higher concentration
1) potential 2) resistance 3) concentration (4) dissociation 100. The unit used to express conductivity is 1) ohm 2) coulomb 3) ampere (4) ohm–1 101. The specific conductance of an electrolyte 1) increases with increase in temperature 2) decreases on dilution 3) depends on the nature of the electrolyte (4) all the above statements are correct
1) 100 / AC 2) AC / 1000 3) C / 1000 A (4) 1 / 1000 AC 103. The molar conductivity of a solution of any electrolyte is the product obtained by multiplying 1) specific conductivity of the solution and the molecular weight of the electrolyte 2) reciprocal of specific conductivity of solution and number of litres of solution containing a mole of the electrolyte (3) specific conductivity and the number of c.c of solution containing a mole of the electrolyte 4) reciprocal of specific conductivity of the solution and number of c.c of solution containing a mole of the electrolyte
1) CH3COOH 2) NH4OH 3) NaCl (4) Na2SO4 105.The specific conductance of 0.01 M NaCl solution is 0.12 Sm–1. The equivalent conductance is 1) 106. Specific conductance of 0.1M nitric acid is  Its molar conductance in 
(1) 630 2) 315 3) 100 4) 6300 107. When a solution of a weak electrolyte is diluted 1) specific conductance increases 2) specific conductance increases but equivalent conductance decreases 3) both specific conductance and equivalent conductance decrease (4) specific conductance decreases and equivalent conductance increases
3) independent of the ionic conductances 4) equal to the difference of ionic conductances 109.The equivalent conductance at infinite dilution of NaCl, HCl and sodium acetate at 298 K are 126.45, 426.16 and 91.0 ohm– 1cm2 respectively. The value of equivalent conductance of acetic acid at the same temperature is 1) 110. In the electrolysis of dil. H2SO4 using platinum electrodes 1) (3) oxygen is evolved at the anode 4) no chemical change occurs
1) gram at. mass 2) gram mol. mass (3) gram eq. mass 4) none of these 112.How many coulombs of electricity are consumed when 200 mA current is passed through CuSO4 for 30 min ? 1) 216 2) 36000 (3) 360 4) 6000 113.The amount of silver deposited on passing 2.0 Faraday of electricity through an aqueous solution of AgNO3 is 1) 54.0 g 2) 108.0 g (3) 216.0 g 4) 324.0 g 114.When 9.65 coulombs of electricity is passed through a solution of silver nitrate ( At mass of Ag = 108.0 gmol– 1). The amount of silver deposited is 1) 6.4 mg (2) 10.8 mg 3) 21.2 mg 4) 16.2 mg 115. The quantity of electricity required to liberate 112 cm3 of H2 at STP from acidified water is 1) 1 faraday (2) 965 coulombs 3) 86500 coulombs 4) 0.1 faraday 116. Electric current is passed through a silver nitrate solution using silver electrodes. 10.79 g of silver was found to be deposited on the cathode. If the same amount of electricity is passed through copper sulphate solution using copper electrodes, the mass of copper deposited on the cathode is 1) 6.4 gm (2) 3.2 gm 3) 12.8 gm 4) 1.6 gm 117. A current of electricity is passed through silver voltameter connected to a water voltameter. The cathode of the silver voltameter weighed 0.108 g more at the end of electrolysis. Volume of oxygen evolved at S.T.P. is 1) 11.2 ml 2) 22.4 ml (3) 5.6 ml 4) 56 ml 118. A current of electricity is passed through a copper voltameter and water voltameter connected in series. If the copper anode of the copper voltameter now weighs 16 mg less, hydrogen liberated at the cathode of the water voltameter measured at S.T.P. is about 1) 4.0 ml (2) 5.6 ml 3) 6.4 ml 4) 8.0 ml 119. The ratio of mass of hydrogen liberated and magnesium deposited by the same amount of electricity from H2SO4 and MgSO4 is? 1) 1 : 8 (2) 1 : 12 3) 1 : 16 4) 1 : 32 120.Electrolysis of KCl. MgCl2, 6H2O gives 1) potassium only 2) magnesium only (3) magnesium and chlorine 4) potassium & magnesium 121. NaOH is manufactured by electrolysis of brine solution. The products of the reaction are (1) Cl2 and H2 2) Cl2 and Na 3) Cl2 and sodium amalgam 4) Cl2 and O2 122. When a solution of an electrolyte is progressively diluted, the dilution reaches a stage known as infinite dilution when the degree of dissociation 1) exceeds 1.0 (2) is equal to 1.0 3) is exactly 0.5 4) is zero 123. Salts of metal A and B were separately electrolysed. Atomic mass of A is 108 and that of B is 64. At the end of electrolysis the mass of A and B deposited were 5.4 g and 1.6 g respectively. The valencies of A and B are 1) 2, 1 (2) 1, 2 3) 1, 1 4) 2, 2 124. The correct order os equivalent conductance at infinite dilution of LiCl, NaCl, KCl is 1) LiCl > NaCl > KCl (2) KCl > NaCl > LiCl 3) NaCl > KCl > LiCl 4) LiCl > KCl > NaCl 125.Product of specific conductance and volume of solution containing 1 gram eq. mass of electrolyte is called 1) molar conductance (2) equivalent conductance 3) electronic conductance 4) none 126. A solution of sodium sulphate in water is electrolysed using inert electrodes. The products formed at the cathode and anode respectively are (1) H2, O2 2) O2, H2 3) O2, Na 4) O2, SO2 127. Electrolysis of brine gives a mixture of 1) caustic soda and chlorine (2) caustic soda, chlorine and hydrogen 3) caustic soda and hydrogen 4) hydrogen, chlorine and oxygen
1) sodium & oxygen 2) sodium & hydrogen 3) hydrogen & oxygen (4) sodium & chlorine 129. Quantity of electricity which liberates 8 grams of oxygen from acidified water is 1) one volt 2) one amphere 3) one coulomb (4) one faraday 130. Assuming complete ionisation, the total number of ions furnished by one mole of ferric alum Fe2 (SO4)3 (NH4)2SO4. 24H2O is (1) 8 N 2) 6 N 3) 9 N 4) 7 N 131. Which one of the following is not a conductor of electricity? (1) Solid NaCl 2) Cu 3) Fused NaCl 4) Brine solution 132. Which one of the following is a weak acid? 1) HCl 2) HI 3) HBr (4) HF 133. Specific conductance of an electrolyte solution is 6.3 ohm–1 m–1. The molecular conductance in Sm2 mol – 1 is (1) 630 × 10– 4 2) 315 × 10– 4 3) 100 × 10– 4 4) 6300 × 10– 4 134. A is a stronger acid than B, if 1) B is more easily decomposed than A when melted 2) A is not as corrosive as B (3) B is less ionized than A when dissolved in a solvent 4) A is displaced from its salts by B
1) increases on dilution 2) does not change considerably on dilution (3) decreases on dilution 4) depends on density
(1) 3.296 g 2) 6.592 g 3) 0.3296 g 4) 1.648 g 139.When a quantity of electricity is passed through CuSO4 solution, 0.16 g of Cu gets deposited. If same quantity of electricity is passed through acidulated water, then the volume of H2 liberated at STP is [At Wt. Cu = 64] (1) 56 Cm3 2) 4.0 Cm3 3) 8.0 Cm3 4) 604 Cm3 140. The quantity of electricity required to liberate 1g equivalent mass of an element is called 1) ampere 2) volt 3) ohm (4) faraday 141. Which of the following alkali metal ions has lowest ionic mobility in aqueous solution (1) Na+ 2) Li+ 3) Cs+ 4) Rb+ 142. An ionizing solvent has 1) a low values of dielectric constant and polarity (2) a high value of dielectric constant and polarity 3) a high value of dielectric constant but low value of polarity 4) a low value of dielectric constant but high value of polarity
(1) silver acts as cathode (2) zinc acts as cathode 3) silver loses electrons4) zinc gains electrons 144.The hydrogen electrode is dipped in a solution of pH 3 at 250C. The potential would be (2.303 RT/F = 0.059 V) 1) 0.177 V (2) -0.177 V 3) 0.087 V 4) 0.059 V 145. The E.M.F. of a galvanic cell constituted with the electrodes Zn2+ / Zn (-0.76 V) and Cu2+ / Cu (0.34 V) is 1) 0.42 V (2) 1.1 V 3) -1.1 V 4) -0.42 V 146. The standard reduction potential, E0, for the half cell reactions are Zn2+ + 2e – = Zn E0 = -0.76 V Fe2+ + 2e – = Fe E0 = -0.41 V The emf or the cell involving the reaction Fe2+ + Zn ↔ Fe + Zn2+ is 1) -0.35 V 2) +1.17 V (3) +0.35 V 4) -1.17 V 147. Normal aluminium electrode coupled with normal hydrogen electrode given an E.M.F. of 1.66 volts. So the standard electrode potential of aluminum is (1) -1.66 volts 2) +1.66 volts 3) -0.83 volt 4) +0.83 volt 148. Standard zinc electrode is coupled with another standard electrode to form a cell whose E.M.F. was found to be 1.6 volts, reduction taking place at the zinc electrode. If the standard reduction potential of the zinc electrode is -0.76 volt, standard reduction potential of the other electrode is (1) -2.36 volt 2) +0.84 volt 3) +2.36 volt 4) -0.84 volt 149.  A Daniel cell contains 0.1M ZnSO4 solution and 0.01 M CuSO4 solution at its electrodes. E.M.F. of the cell is
1) 1.10 V 2) 1.04 V 3) 1.16 V (4) 1.07 150. The reaction ½ H2 (g) + AgCl (s) ↔ H+ (aq) + Cl – (aq) + Ag (s) occurs in the galvanic cell 1) Ag | AgCl (s) | KCl (aq) || AgNO3 (aq) | Ag 2) Pt | H2 (g) | HCl (aq) || AgNO3 (aq) | Ag (3) Pt | H2 (g) | HCl (aq) | AgCl (s) | Ag 4) Pt | H2 (g) | HCl (aq) | AgCl (s) | Ag
Directory: doc doc -> Enterprise Network Management iPost: Implementing Continuous Risk Monitoring at the Department of State doc -> Concept stage doc -> Application for acem doc -> What programs are available? doc -> 100 Village Primary School Music Classrooms doc -> Observational Assessment of Teaching Practices Teaching Assessment Initiative Proposal Submitted to The Teachers for a New Era project doc -> Concept stage doc -> Traditional British values Download 230.37 Kb. Share with your friends:
|
for the 
Cl2(g) + 2e− → 
2) 
(3) 
4) 
2) 
3) 
(4) 
is discharged at the cathode 2) H+ is evolved at the anode