ECAT Chemistry Chapter 10 Electrochemistry Online Test With Answers

image
image
image

ECAT Chemistry Chapter 10 Electrochemistry Online Test

Sr. # Questions Answers Choice
1 Corrosion reaction are Spontaneous redox reaction Non-spontaneous acid-base reactions Spontaneous acid-base reactions None of these
2 Standard reduction of Zn = -0.76 V and that of Ni is -0.25 V. On coupling them by a salt bridge which of these will act as anode Salt bridge will act as anode Zn will act as anode Ni will act as anode None of these
3 Zn does not displace Mg from MgSO4solution because Zn is more electropositive than Mg Zn is below Mg in electropositive series Zn is above Mg in electrochemical series Zn is trivalent Mg is divalent
4 Fe can displace Cu form CuSO4solution because Fe is ferromagnetic Fe is below Cu in electrochemical series Fe is above Cu in electrochemical series Fe exists in divalent oxidation state
5 Which of the following will be good conductor of electricity Pure distilled water Molten NaCl Dilute solution of glucose Chloroform
6 In KO2the oxidation state of oxygen is -2 -1 +1/2 -1/2
7 F2, Cl2, Br2and l2lie below SHE is the Electro chemical series that is why these Undergo reduction Undergo oxidation Liberate H<sub>2</sub>gas with steam None of these
8 In the electrolysis of fused bauxite (Al2O32H2O) with fused Cryolite (Na3AlF6) using carbon rods as anode. The product obtained at cathode is Na metal F<sub>2</sub>gas Al metal O<sub>2</sub>gas
9 During redox reaction an oxidizing agent Gains electrons Is oxidized Loses electrons Hydrolysed
10 When aqueous solution of NaOH is electrolysed useing graphite electrodes, the product obtained at anode is O<sub>2</sub>gas H<sub>2</sub>gas Na metal Na<sub>2</sub>O
11 In passage of electricity through aqueous solution of AgNO3silver dissolves at anode to form Ag+, the electrodes are Silver metal Pt metal Graphite Copper metal
12 In the reaction K2Cr2O7+ HCl + CrCl3+ Cl2+ H2O the element which is reduced is K Cl Cr H
13 Li has the lowest reduction potential while the element with highest reduction potential is H F O N
14 Which statement is incorrect for balancing of redox reactions by ion-electron method The reaction is splitted into two half reactions H<sub>2</sub>O and H<sup>+</sup>ions are added for acidic or neutral reaction to balance O and H atoms To balance H, HCi, is added To balance O and H in the alkaline reaction OH<sup>-</sup>added
15 Metals like Fe, Mg, Al, Cr, Zn have more negative reduction potentials that is whey These don't react with steam These react very slowly with steam to liberate H<sub>2</sub>gas These react rapidly with steam to produce the metallic oxides and liberate H<sub>2</sub>gas These react with cold water violently
16 Coinage metals like Au, Pt, Ag and Cu are the least reactive metals and don't liberate H2gas when treated with acids because These have very high positive values of reduction potentials These have very high negative values of reduction potentials Their ionization potentials are lowest Their reduction potentials are close to SHE
17 Metals which are above SHE in electrochemical series Can liberate H<sub>2</sub>from acid Cannot liberate H<sub>2</sub>from acid Cannot always liberate H<sub>2</sub>from acid None of these
18 Cu H N O
19 Strong reducing agents gave Greater positive value of standard reduction potential Greater negative value of standard reduction potential Lesser positive value of standard reaction potential None of these
20 In a compound an atom has negative oxidation state because Atom is negatively charged Atom acts as cathode Atom is more electronegative Atom has lowest ionization energy
21 The oxidation number of chromium in K2Cr2O7is 14 12 6 None of these
22 The oxidation state of an element is zero when It forms an oxide It forms hydride It is in free state Only for noble gases
23 The oxidation number of Mn is KMnO4is +2 +4 +6 +7
24 Oxidation number of oxygen in OF2is +1 -1 +2 -2
25 The oxidation number of H is -1 in the compound H<sub>2</sub>O H<sub>3</sub>BO<sub>3</sub> NaOH NaH
26 Which statement is correct for the fuel cells These cells operate at low temperature These cells operate at low temperature No catalyst used for the formation of water MnO<sub>2</sub>is used as electrolyte
27 Which statement is incorrect for NICAD battery The electrolyte is alkali Cd acts as anode MnO<sub>2</sub>acts as electrolyte NiO<sub>2</sub>acts as cathode
28 Lead accumulator stops discharging current when Lead at anode converted to PbO<sub>2</sub> PbO<sub>2</sub>at cathode converted to Pb Both electrodes are completely covered with PbSO<sub>4</sub> Both electrodes are completely covered with Pb(OH)<sub>2</sub>
29 Silver oxide battery has a voltage of 2.0 V 1.5 V 2.5 V 1.0 V
30 During electrolysis of KNO3, H2is evolved Anode Cathode Both a and b None
Download This Set
×