mcqs electrochemical and redox reaction

Electrochemistry & Redox ReactionsQuestions: 1. The variation of equivalent conductance vs decrease in concentration of strong electrolyte is correctly given in the plot 2. How many coulombs of electricity are required for reduction of 1 mol of ? (a) 96500 C (b) (c) (d) 3. How many coulombs of electricity are required for the oxidation of 1 mole H2O to O2? (a) (b) (c) (d) 4. How long 2.5 amp of current is passed to supply 54000 C of charge? (A) 1 hr (b) 2.5 hr (c) 6 hr (d) 9 hr 5. Which of the following statement is correct for a galvanic cell. (a) Reduction occurs at cathode (b) Oxidation occurs at anode (c) Electrons flow from anode to cathode (d) All the statements are correct. 6. . A cell represented above should have e.m.f. (a) Positive (b) Negative (c) Zero (d) None is correct 7. In electrochemical corrosion of metals, the metal undergoing corrosion: (a) Become anode (b) Become cathode (c) Become inert (d) None is correct 8. The chemical reaction; is an example of: (a) Redox process (b) Reversible process (c) Oxidation (d) Reduction 9. Which of the following is anodic reaction (a) (b) (c) (d) None of the above. 10. On passing electricity the quantity of deposition depends upon (a) Shape of electrolytes (b) size of vessel (c) Quantity of electricity that passes through the electrolyte (d) None of the above factors. 11. The value of molar conductivity of HCl is greater that of Nacl at a particular temperature because (a) molecular mass of HCl is less than that of NaCl (b) Velocity of ions is more than that of ions (c) HCl is strongly acidic (d) ionization of HCl is larger than that of NaCl. 12. The standard reduction potentials at 298K for the following half reactions are given against each: which of strongest reducing agent? (a) Zn (s) (b) Cr (s) (c) H2 (g) (d) 13. A solution containing one mole per litre of each is being electrolysed by using inert electrodes. The values of standard electrode potentials in volts (reduction potentials) are: With increasing voltage, the sequence of deposition of metals on the cathode will be: (a) Ag,Hg.Cu,Mg (b) Mg,Cu,Hg,Ag (c) Ag,Hg,Cu (d) Cu,Hg,Ag 14. Which of the following reaction actually take place? (a) (b) (c) (d) 15. On electrolyzing a solution of dilute H2SO4 between platinum electrodes, the gas evolved at the anode is (a) SO2 (b) SO3 (c) O2 (d) H2 16. In electrolysis of very dilute NaOH using platinum electrodes (a) H2 is evolved at cathode (b) NH3 is produced at anode (c) Cl2 is obtained at cathode (d) O2 is produced at anode 17. When the same quantity of electricity is passed through the solution of different electrolytes in series, the amounts of product obtained are proportional to their (a) Atomic weights (b) Chemical equivalents (c) gm. Molecular volume (d) gm. Atomic ions 18. A certain current liberate 0.5 g of hydrogen in 2 h. How many grams of copper can be liberated by the same current flowing for the same time in a copper sulphate solution? (a) 12.7 gms (b) 15.9 gms (c) 31.8 gms (d) 63.5 gms 19. The standard electrode potential of the half cells are given below. The e.m.f given below (a) -0.32 V (b) + 0.32 V (c) + 1.20 V (d) -1.20 V 20. When electricity is passed through aqueous solution of aluminum chloride, 13.5 g of Al are deposited. The number of faradays of electricity passed must be: (a) 2.0 (b) 1.5 (c) 1.0 (d) 0.5 21. The electroplating with chromium is undertaken because: (a) electrolysis of chromium is easier (b) chromium can form alloys with other metals (c) Chromium gives a protective and decorative coating to the base metal (d) of high reactivity of chromium metal 22. Which of he following is a strong electrolyte? (a) Ca(NO3)2 (b) HCN (c) H2SO3 (d) NH4OH 23. The resistance of 1 N solution of acetic acid is 250 ohm, when measured in a cell of cell constant 1.15 cm-1. The equivalent conductance (in ohm-1 cm2 equiv-1) of 1 N acetic acid is: (a) 4.6 (b) 9.2 (c) 18.4 (d) 0.023 24. Oxidation is a process of (a) Loss of electrons (b) Gain of electrons (c) increase in the negative valency (d) decrease in positive valency 25. When zinc is added to CuSO4 solution, copper is precipitated, it is so because of (a) Reduction of Zn (b) Reduction of Cu2+ (c) Hydrolysis of CuSO4 (d) Reduction 26. White PP reacts with caustic soda, the products are PH3 and NaH2PO2. This reaction is an example of (a) Oxidation (b) Reduction (c) Disproportionation (d) neutralization 27. The charge on cobalt in is 28. In which reaction there is change in O.N. of N atom (a) 2NO2 = N2O4 (b) (c) (d) 29. Select the compound in which chlorine is assigned the oxidation number + 7. (a) HClO4 (b) HClO2 (c) HClO3 (d) HCl 30. In ferrous ammonium sulphate oxidation number of Fe is (a) +3 (b) +2 (c) 0 (d) -2 31. O.N. of P in KH2PO2 is (a) +1 (b) +3 (c) +5 (d) -4 32. The O.N. of nitrogen is is (a) -1 (b) +2 (c) +5 (d) -2 33. The oxidation state of nitrogen in N3H is (a) (b) +3 (c) -1 (d) 34. Oxidation number of iron in potassium ferrocyanide is (a) +2 (b) +3 (c) +4 (d) +1 35. If three electrons are lost by a metal ion M+3, its final oxidation number would be (a) Zero (b) +6 (c) +2 (d) +3 36. Chlorine is in + 1 oxidation state in (a) HCl (b) HClO4 (c) ICl (d) Cl2O 37. Oxidation state of oxygen in hydrogen peroxide is (a) -1 (b) +1 (c) 0 (d) -2 38. The standard reduction potential values of three metallic cations x, y, z are 0.52, - 3.03 and -1.18 V respectively. The order of reducing power of the corresponding metals is (a) y > z > x (b) x > y > z (c) z > y > x (d) z > x > y 39. The colour of changes from red orange to lemon yellow on treatment with aqueous KOH because of (a) reduction of Cr (VI) to Cr (III) (b) formation of chromium hydroxide (c) conversion of dichromate ion to chromate (d) oxidation of potassium hydroxide to potassium peroxide 40. Which substance is serving as a reducing agent in the following reaction (a) H2O (b) Ni (c) H+ (d) 41. For the redox reaction Correct stoichiometric coefficients of (a) 2,5,16 (b) 16,5,2 (c) 5,16,2 (d) 2,16,5 42. In which of the following reaction H2O2 is a reducing agent (a) (b) (c) (d) 43. The oxidation number of P in Mg2P2O7 is (a) +3 (b) +2 (c) +5 (d) -3 44. In the reaction the sulphuric acid acts as: (a) Oxidising agnet (b) Reducing agnet (c) Catalyst (d) Acid as well as oxidant 45. A 2.5 mol of hydrazine N2H4 loses 25 mole of electrons in being converted to a new compound X. Assuming that all of the nitrogen appears in the new compound, what is the oxidation state of nitrogen in compound X? (a) -1 (b) -2 (c) +3 (d) +4 46. Oxidation number of O is H2O2 will be (a) -2 (b) -1 (c) +1 (d) +2 47. Which of the following is serving as a reducing agent in the following reaction (a) H2O (b) Ni (c) H+ (d) 48. The oxidation number of S in is (a) +8 (b) +6 (c) +4 (d) 0 49. The oxidation number of chromium in K2Cr2O7 is (a) -6 (b) +6 (c) +2 (d) -2 50. The oxidation state of Cr in is (a) 4 (b) 6 (c) 7 (d) -6 1 *** Mrs Shallu Aggarwal Contact #. 2230216 Mobile #. 98152-08983 ***