Practice Test


1) Zinc - copper couple that can be used as a reducing agent is obtained by


2) According to Faraday's second law of electrolysis when the same quantity of electricity is passed through different electrolytes, the amounts of different substance produced at the electrodes are directly proportional their


3) The theory of ionization of electrolytes was proposed by


4) When a piece of copper wire is immersed in a solution of silver nitrate, the colour of solution becomes blue. This is due to the


5) The electrode potential of hydrogen electrode at 298 K is assumed to be


6) The e.m.f. of a cell is 1.3 V. The positive electrode has a potential of 0.5 V. The potential of negative electrode is


7) Which of the following statement is correct about electrochemical cell?


8) Molten NaCl conducts electricity due to the presence of


9) In a galvanic cell, which one of the following statement is not correct?


10) The electrode potential of oxidation half cell


11) When zinc rod is directly placed in copper sulphate solution


12) The electrochemical cell stops working after some time because


13) A metal having negative reduction potential when dipped in the solution of its own ions has a tendency


14) The standard electrode potential of four electrodes I, II, III and IV are -2.65, -1.72, - 0.80 and 0.72 respectively. The highest chemical activity will be exhibited by


15) The quantity of electricity needed to liberate 0.1 gram equivalent of an element at the electrode is


16) Which of the following is not a good coductor of electricity?


17) The cell constant is product of resistance and


18) The product of specific resistance and specific conductance is equal to


19) On dilution the molar conductance of an electrolyte


20) The fraction of the current carried by an ion is called its


21) In the concentration cell, the electrical energy is due to


22) The decrease in the molar conductance of a strong electrolyte with increase in concentration is due to


23) The dissociation of a weak electrolyte obeys the law of mass action. It was found by


24) Four alkali metals A, B, C and D are having respectively standard reduction potential as -3.05, -1.66, -0.40 and 0.08 V. Which one will be the most reducing?


25) A half reaction in an electrochemical cell is one that


26) When an aqueous solution of sulphuric acid is electrolysed, the ion discharged at the anode is


27) During rusting of iron, it gets


28) Galvanised iron sheets are coated with


29) In which of the following will the corrosion of iron be most rapid?


30) The unit of electrochemical equivalents is


31) Out of Cu, Ag, Fe and Zn, the metal which can displace all others from their salt solution is


32) The best conductor of electricity is a solution of


33) The cathode reaction in electrolysis of dilute sulphuric acid with platinum electrodes is


34) The electrode potentials of four elements A, B, C and D are 1.24 V, 0.67 V, -0.26 V and -1.42 V respectively. The most reactive among these is


35) The e.m.f. of a cell reaction is positive when the free energy of the cell reaction is


36) A depolarizer used in dry cell is


37) Two electrolytic cells, one containing acidified ferrous sulphate and other containing acidified ferric sulphate are connected in series. The ratio of iron deposited at cathodes in the two cells will be respectively


38) The standard electrode potential of the elements A, B and C are 0.68, -2.50 and -0.50 V respectively. The order of their reducing power is


39) The main function of salt bridge is


40) The conductance of one cm cube of a solution represents its


41) Which of the following solutions will have highest equivalent conductance?


42) When a lead storage battery is charged, it acts as


43) If a salt bridge is removed between the two half cells in an experiment, the voltage


44) Strong electrolytes are those which


45) Which of the following aqueous solutions will conduct electricity quite well?


46) Which of the substance Na, Hg, S, Pt and graphite can be used as electrodes in electrolytic cells having aqueous solution?


47) The solution of copper sulphate in which copper rod is dipped is dipped is dilutes to 10 times. The reduction potential of copper


48) What will happen if a copper spoon is used to stir a solution of aluminium nitrate?


49) What weight of copper will be deposited by passing 2 Faradays of electricity through a cupric salt (At. Mass = 63.5)?


50) How many Faradays are required to liberate 8 g of hydrogen?


51) If the specific conductance and conductance of the solution are same, then its cell constant is equal to


52) How long 2.5 amp of current is passes to supply 54000 C of charge?


53) A quantity of electricity equal to 3 Faraday is required to electroplate a given metal. If a current of 5 amp is used in the electrolytic cell, how long will it take to electroplate the metal?


54) Salts of A (at.mass = 7), B (at. Mass = 27) and C (at. Mass = 64) were electrolysed under identical condition using the same quantity of electricity. It was found that when 2.1 g of A was deposited, the weights of B and C deposited were 2.7 g and 9.6 g. The valencies of A, B and C are respectively


55) The potential of hydrogen electrode having pH = 10 is


56) Standard zinc electrode is coupled with another standard electrode to form a cell whose e.m.f. was found to be 1.60 volts, reduction taking place at zinc electrode. If the standard reduction potential of the zinc electrode is -0.76 V, standard reduction potential of the other electrode is


57) When a solution of an electrolyte is heated the conductance of the solution


58) The charge required to liberate 11.5 g of sodium chloride is


59) Which of the following metals can deposit copper from copper sulphate solution?


60) During the electrolysis of fused NaCl, the anodic reaction is


61) The conductance which decreases with dilution is


62) The standard reduction potential values of three metallic cations X, Y and Z are 0.52, -3.03 and -1.18 V respectively. The order of reducing power of corresponding metals is


63) The specific conductance of solution depends upon


64) In the electrolytic cell, flow of electrons is from


65) In a hydrogen - oxygen fuel cell, combustion of hydrogen occurs to


66) Consider a titration of potassium dichromate solution with acidified Mohr's salt solution using diphenylamine as indicator. The number of moles of Mohr's salt required per mole of dichromate


67) Which of the following is not anodic reaction in an electrochemical series?


68) For a redox reaction to occur spontaneously, the e.m.f. of the cell should be


69) Copper sulphate cannot be stored in a container made of zinc because


70) The standard reduction potentials of zinc and silver are -0.76 and 0.8V respectively. Which of the following reactions actually occurs?


71) The reference calomel electrode is made from


72) One Faraday is equal to


73) Which of the following gains electrons more easily?


74) Which of the following can be considered as a weak electrolyte?


75) The number of electrons involved in the reaction when 1 F of electricity is passed through an electrolytic solution is


76) The units for cell constant are


77) Which of the following relations is correct for Kohlrausch's law?


78) The units of conductivity are


79) The reaction occurring at cathode in Nelson's cell is


80) An example of a simple fuel cell is


81) Rust is a mixture of


82) In lead storage battery, at cathode


83) If m is the mass of substance (having equivalent weight E) produced or consumed when Q quantity of electricity is passed, then


84) A solution of sodium sulphate in water is electrolysed using inert electrodes. The products at the cathode and anode are respectively.


85) In the Leclanche dry cell, anode is


86) Copper displaces which of the following metal from its salt solution?


87) Which of the following solutions will turn blue on adding a piece of copper metal to it?


88) The units of molar conductance are


89) As a lead storage battery is charged


90) One Faraday of electricity will liberate one gram atom of metal from a solution of


91) Which of the following batteries is rechargeable?


92) The calomel electrode used as reference electrode contains


93) Which of the following compounds is the most easily reduced?


94) The following four colourless salt solutions are placed in separate test tubes and a strip of copper is placed in each. Which solution finally turns blue?


95) The standard reduction potential of Ag, Cu and Zn are 0.80 V, 0.34 V and -0.76 V respectively. Which one of the following can be stored?


96) The total number of electrons involved in the reaction when one Faraday of electricity is passed through an electrolytic solution is


97) Which of the following solutions will have the highest specific conductance?


98) In salt bridge, generally KCl is used because


99) The value of molar conductance of HCl is more than that of NaCl at a particular temperature because


100) Which of the following reactions is not possible?


101) Which of the following conducts electricity?


102) In a Daniell cell constructed in the laboratory, the voltage observed was 0.9 V instead of 1.10 V of the standard cell. A possible explanation is


103) The reduction potential of hydrogen electrode will be positive if


104) What products are expected from the dispro portionation reaction of hypochlorous acid?


105) At anode in the electrolysis of fused sodium chloride


106) The reference electrode is made by using


107) Corrosion is basically a


108) Time required to deposit one millimole of aluminium metal by the passage of 9.65 amperes through molten electrolyte containing aluminium ions is


109) Galvanization includes plating iron with


110) Which of the following (1 M) conducts more electricity?


111) Which of the following statements is true for the electrochemical Daniell cell?


112) Which of the following reactions is used to make a fuel cell


113) The products formed when an aqueous solution of NaBr is electrolysed in a cell having inert electrode are


114) The efficiency of a fuel cell is given by


115) Kohlrausch's law states that at


116) An increase in equivalent conductance of a strong electrolyte with dilution is mainly due to


117) Among the following cells
Leclanche cell (I), Nickel - Cadmium cell (II), Lead storage battery (III), Mercury Cell (IV)
primary cell are


118) Standard electrode potential of three metals X, Y and Z are - 1.2 V, + 0.5 V and -3.0 V respectively. The reducing power of these metals will be:


119) The value of equilibrium constant for the feasible cell reaction is


120) Which atom in the following reaction undergoes a change of oxidation state of -5?


121) 10800 C of electricity through the electrolyte deposited 2.977 g of metal with atomic mass 106.4 a.m.u. The valency of metal cation is


122) Four alkali metals A, B, C and D are having respectively standard electrode potentials as -3.05, -1.66, -0.40 and 0.80 V. Which will be the most reducing?


123) A standard hydrogen electrode has zero electrode potential because


124) The following four colourless salt solutions are placed in separate test tubes and a strip of a copper is placed in each. Which of the following solutions will finally turn blue?


125) The ratio of molar conductance and specific conductance are


126) When lead storage battery discharges


127) Galvanised iron sheets are coated with


128) In a Leclanche dry cell, anode is


129) Which of the following is not correct for galvanic cell?


130) Which of the following plots represents correctly the variation of equivalent conductance with dilution for a strong electrolyte?


131) The expected conductometric titration for HCl against NaOH is