CBSE AND AIPMT: ELECTROCHEMISTRY

TEST PAPER NO.03 TOPIC : ELECTROCHEMISTRY M.M. 50 TIME: 3 HRS. Name of Student________________________________ Roll No. _______________ Q.NO. 1-10 carries 1 mark, 11-20 2 marks, 21-25 carries 3 marks, 26 carries 5 marks. 1. Write the reaction involved in Lead Storage Battery? 2. Why Zn-HgO cell volatage remains constant during its life? 3. Define conductivity and molar conductivity? 4. The conductivity of 0.20 M solution KCl at 298 K is 0.0248 S cm-1 Calculate its molar conductivity? 5. Write the unit of molar and equivalent conductivity? 6. Define Kohlrausch law? 7. What are the units of molar and equivalent conductance? 8. Calculate the potential of hydrogen electrode in contact with a solution pH=10 9. Calculate the equilibrium constant of the reaction: Cu(S) + 2Ag+(aq) Cu2+ + 2Ag(s) Eocell = 0.46 V 10. Can we store copper sulfate solution in a zinc pot? 11. What are the factors which affect conductance of ions in solution? 12. A CuSO4 solution is electolysed for 10 minutes with a current of 1.5 amperes. What is the mass of copper deposited at cathode? (Cu = 63.5 u) 13. Explain the Fuel Cell with equations and its application? 14. Explain the mechanism of corrision with equation and prevention? 15 What is the effect of dilution on weak and strong electrolyte. Explain graphically? 16 How much electrictiy in terms of Faraday is required to produce: a. 20 gm of Ca from molten CaCl2 b. 40 gm of Al from molten Al2O3 17. How much electricity is required in columb for the oxidation of a. 1 mol of H2O to O2 b. 1 mol of FeO to Fe2O3 18. A sp;itopm pf Ni(NO3)2 is electrolysed b/w platinum electrodes using a current 5 amperes for 20 minutes. What mass of Ni is deposited at the time of cathode? 19. Predict the products of electrolysis in each of the following: a. An aqueous solution of AgNO3 with silver electrode. b. An aqueous soluiton of AgNO3 with platinum electrodes. c. A dilute solution of H2SO4 with platinum electrodes. d. An aqeous solution of CaCl2 with platinum electrodes. 20. The electrical resistance of a column of 0.05 mol L-1 NaOH solution of diameter 1 cm and legth 50 cm is 5.55 x 103 ohm. Calculate its resistivity, conductiviy and molar conductivity. 21. Represent the cell in which the following reaction takes place: Mg(s) + 2 Ag+ (0.0001 M) Mg2+ (0.130 M) + 2 Ag (s) Calculate its E(cell) if Eo = 3.17 V, Go and Kc 22. How much charge is required for the following reductins: a. 1 mol of Al3+ to Al b. 1 mol of Cu2+ to Cu c. 1. mol of MnO4-1 to Mn2+ 23. Three electrolytic cells A,B,C containing solutions ZnSO4, AgNO3 and CuSO4 respectively are connected in series. A steady current of 1.5 amperes was passed through them until 1.45 gm of silver deposited at the cathode of cell B. How long did the current flow? What mass of copper and zinc were deposited? 24 Suggest the list of metals that are extracted electrolytically? If a current of 0.5 ampere flows through a metallic wire for 2 hours, then how many electrons would flow through the wire? 25 Explain the difference b/w Electrochemical and Galvanic cell? What are electrolytes? How are electrolytes responsible for conduction in soltuion? 26 a. Calculate om for CaCl2 and MgSO4 from the given data: oca2+ = 119 oCl-= 76.3 omg2+ = 106 oSO4-2 = 160 S cm2mol-1  om for NaCl, HCl and NaAc are 126.4,425.9 and 91.0 S cm2mol-1 respectively Calculate om for HAc.