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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 1501. |
Which of the following reaction is anodic?A. `SO_(4)^(2-)+H_(2)OrarrH_(2)SO_(4)+(1)/(2)O_(2)+2e^(-)`B. `H^(+)+e^(-)rarr(1)/(2)H_(2)`C. `Ag^(+)+e^(-)rarrAg`D. `H_(2)O+e^(-)rarrOH^(-)+(1)/(2)H_(2)` |
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Answer» Correct Answer - A In anodic half reaction, oxidation i.e., loss of electrons takes place. |
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| 1502. |
A net cell reaction is given as `Cr+3H_(2)O+Ocl^(-)rarrCr^(3+)+3Cl^(-)+6OH^(-)` The species undergoing reduction isA. CrB. `H_(2)O`C. `Ocl^(-)`D. `Cl^(-)` |
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Answer» Correct Answer - C In going from `Ocl^(-)` of `Cl^(-), Cl` changes its oxidation from +1 to 01, by undergoing gain of electrons. |
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| 1503. |
The reaction occuring at the anode during the working of alkaline dry cell -A. `Zn + H_(2)O to ZnO + 2 OH^(-) + 2e^(-)`B. `Zn + 2 OH^(-) to ZnO + H_(2)O + 2 e^(-)`C. `Zn to Zn^(2+) + 2e^(-)`D. `Zn^(2+) + 2e^(-) to Zn` |
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Answer» Correct Answer - B During working the reaction at anode is oxidation of Zn to form `ZnO` as `Zn + 2 OH^(-) to ZnO + H_(2)O + 2 e^(-)` |
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| 1504. |
What is rate determining step in a complex reaction ? |
| Answer» The overall rart of a reaction is controlled by the slowest step in a raeaction is called the rate determining step in a complex reaction. | |
| 1505. |
When a fuel cell is dischargedA. `H_(2)O` is evolvedB. lead sulphate is consumedC. lead is formedD. sulphuric acid is consumed |
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Answer» Correct Answer - A When a fuel cell is discharged , `H_(2)O` is evolved as - `2H_(2) + O_(2) to2 H_(2)O` |
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| 1506. |
Which cell has a constant voltage thorughout its life ?A. Leclanche cellB. Electrolytic cellC. Mercury cellD. Daniel cell. |
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Answer» Correct Answer - C Mercury cell has a constant voltage through out its life . |
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| 1507. |
For the reaction `N_(2)(g)+3H_(2)(g)hArr2NH_(3)(g)` at 298K, enthalpy and entropy changes are -92.4 kJ and -198.2 `JK^(-1)` respectively. Calculate the equilibrium constant of the reaction `(R=8.314JK^(-1)mol^(-1))`. |
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Answer» Correct Answer - `6.958xx10^(5)` `DeltaG=DeltaH-TDeltaS`. Calculate `DeltaG`. |
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| 1508. |
Assertion: For measuring resistance of an ionic solution, an AC source is used. Reason: Concentration of ionic solution will change if DC source is used.A. Both assertion and reason are true and the reason is the correct explanation of assertion.B. Both assertion and reason are true and the reason is not the correct explanation of assertion.C. Assertion is true but the reason is false.D. Both assertion and reason are false. |
| Answer» Correct Answer - A | |
| 1509. |
Assertion(A) Mercuty cell does not give steady potential Reason (R) In the cell reaction, ions are not involved in solution.A. Both assertion and reason are true and the reason is the correct explanation of assertion.B. Both assertion and reason are true and reason is not the correct explanation of assertion.C. Assertion is true but the reason is false.D. Both assertion and reason are false. |
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Answer» Assertion is false but reason is true, correct assertion ismercury cell gives steady potential Reason is correct as ions are not involved in cell reaction |
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| 1510. |
Assertion: Mercury cell does not give steady potential. Reason: In the cell reaction, inons are not involved in solution.A. Both assertion and reason are true and the reason is the correct explanation of assertion.B. Both assertion and reason are true and the reason is not the correct explanation of assertion.C. Assertion is true but the reason is false.D. Assertion is false but reason is true. |
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Answer» Correct Answer - D Correct Assertion. Mercury cell gives a steady potential. |
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| 1511. |
When an aqueous concentrated solution of lithium chloride is electrolysed using inert electrodes:A. `Cl_2` is liberated at the anodeB. Li is deposited at the cathodeC. as the current flows. pH of the solution around the cathode remains constantD. as the current flows, pH of the solution around the cathode increases |
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Answer» Correct Answer - A::D |
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| 1512. |
In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices. (i) Both assertion and reason are true and the reason is the correct explanation of assertion. (ii) Both assertion and reason are true and the reason is not the correct explanation of assertion. (iii) Assertion is true but the reason is false. (iv) Both assertion and reason are false. (v) Assertion is false but reason is true.Assertion : Mercury cell does not give steady potential.Reason : In the cell reaction, ions are not involved in solution. |
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Answer» (iv) Both assertion and reason are false. |
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| 1513. |
In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices. (i) Both assertion and reason are true and the reason is the correct explanation of assertion. (ii) Both assertion and reason are true and the reason is not the correct explanation of assertion. (iii) Assertion is true but the reason is false. (iv) Both assertion and reason are false. (v) Assertion is false but reason is true.Assertion : For measuring resistance of an ionic solution an AC source is used.Reason : Concentration of ionic solution will change if DC source is used. |
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Answer» (i) Both assertion and reason are true and the reason is the correct explanation of assertion. |
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| 1514. |
In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices. (i) Both assertion and reason are true and the reason is the correct explanation of assertion. (ii) Both assertion and reason are true and the reason is not the correct explanation of assertion. (iii) Assertion is true but the reason is false. (iv) Both assertion and reason are false. (v) Assertion is false but reason is true.Assertion : Electrolysis of NaCl solution gives chlorine at anode instead of O2.Reason : Formation of oxygen at anode requires overvoltage. |
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Answer» (i) Both assertion and reason are true and the reason is the correct explanation of assertion. |
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| 1515. |
Assertion: Electrolysis of NaCl solution gives chlorine at anode instead of `O_(2)`. Reason: Formation of oxygen at anode requires overvoltage.A. Both assertion and reason are true and the reason is the correct explanation of assertion.B. Both assertion and reason are true and the reason is not the correct explanation of assertion.C. Assertion is true but the reason is false.D. Both assertion and reason are false. |
| Answer» Correct Answer - A | |
| 1516. |
which of the following arrangement will procedure oxygen at anode during electrolysis?A. Dilute `H_2SO_4` with Pt electrodesB. Fused NaOH with inert electrodesC. Dilute `H_2SO_4` with Cu electrodesD. Concentrated aq. NaCl with Pt electrodes |
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Answer» Correct Answer - A::B |
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| 1517. |
Cell constant has unit `m^(-1)`. |
| Answer» Correct Answer - T | |
| 1518. |
The conductivity of molten `KCl` is due to the movement of `K^(o+)` and `Cl^(c-)` ions. |
| Answer» Correct Answer - T | |
| 1519. |
Solid `KCl` is a good conductor of electricity. |
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Answer» Correct Answer - F Molten or aqueous solution of `KCl` is a good conductor of electricity. |
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| 1520. |
Molten `Na_(2)SO_(4)` is a good conductor because of mobile electrons. |
| Answer» Correct Answer - T | |
| 1521. |
Cathode is negative terminal both in electrochemical and electrolytic cells. |
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Answer» Correct Answer - F Cathode is `+ve` in electrochemical cell and `-ve` in electrolytic cell. |
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| 1522. |
(a) What do you mean by Electrolytic cell? (b) An electrochemical cell is made of nickel and copper electrodes with their standard reduction potentials -0.25 V and +0.34 V respectively. Select the anode and cathode. Represent the cell and find e.m.f. of the cell. |
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Answer» (b) Anode (Ni), Cathode (Cu) , Cell : `Ni (s)|Ni^(2+)(aq)||Cu^(2+)(aq)|Cu(s)` `E_(cell)^(@)=0.59" V "` |
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| 1523. |
Assertion: Galvanic cells containing hydrogen, methane, methanol etc. as fuels are called fuel cells. Reason: They are designed to convert the energy of combustion of fuels directly into electrical energy.A. if both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertion.C. If assertion is true but reason is falseD. If the assertion and reason both are false. |
| Answer» Correct Answer - A | |
| 1524. |
What are the fuel cells ? How are they different from galvanic cells ? Give the construction of `H_(2), O_(2)` fuel cell ? |
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Answer» A fuel cell is a galvanic cell in which the chenical energy of fuel-oxidant syste m is converted directly into electrical energy. `to` Convertional Galvanic cell converts chemical energy into electrical energy by spontaneous redox reactions. ` to` Fuel cell convert energy of combustion of fuels like hydrogen, meghane etc., into electrical energy. These cause less pollution,. `H_(2)-O_(2)` fuel cell: In this cell, hydrogen and oxygen are bubbled through porous carbon electrodes into Conc. NaOH solution. Electrodes are embedded with suitable catalysts. The electrode reactions are `O_(2(g))+2H_(2)O_((l))overset(+4e^(-))to4OH_((aq))^(-)` (Cathode) `2H_(2_((g)))+4OH_((aq))^(-) to4 H_(2)O_((l)) +4e^(-)` (anode) Overall reaction : `2H_(2_(g))+O_(2_(g))to 2H_(2) O_((l))` The cell function as long as the reacting gases are in supply. The hate of combustion is directly converted into electrical energy. |
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| 1525. |
For the reaction : `Ni(s)+2Ag^(+)(1 M) to Ni^(2+)(1 M) +2Ag(s)` which species gets reduced ? |
| Answer» `Ag^(+)` ions get reduced. | |
| 1526. |
Why does iron gain weight as a result of rusting ? |
| Answer» Bacause the coating of rust `Fe_(2)O_(3).xH_(2)O` is deposited on the surface of earth | |
| 1527. |
In the commercial preparation of aluminum,aluminum oxide `(Al_2O_3)` is electrolysed at `1000^(@)` C. How many coulombs of electricity are required to give 54kg of aluminum ? Assume following reaction takes place at cathode: `Al^(3+)+3e^-to Al`A. `17.3xx10^8`B. `3.21xx10^7`C. `1.82xx10^4`D. `57.6xx10^7` |
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Answer» Correct Answer - D |
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| 1528. |
Which one of the following statements is (are) false in a concentration cell made of Fe in 0.010 M `Fe^(2+)` (aq) and Fe in 0.10 `M Fe^(2+)`?A. The `E_("cell")^(@)=0`B. `DeltaG=0`C. The cell reaction is. `Fe^(2+)(aq.0010M)rarrFe^(2+)(aq0.10M)`D. At equilibrium, the `|Fe^(2+)|_("anode")=|Fe^(2+)|_("cathode")` |
| Answer» Correct Answer - b,c | |
| 1529. |
How many coulombs are provided by a current 0.010 mA in the calculator battery that can operate for 1000 hours?A. 1B. 10C. 0.01D. 36 |
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Answer» Correct Answer - D |
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| 1530. |
How does `H_(2)-O_(2)` fuel cell operate? |
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Answer» At anode: `2H_(2)(g)+4OH^(-)(aq)to4H_(2)O+4e^(-)` At cathode: `underline(O_(2)(g)+2H_(2)O(e)+4e^(-)to4OH^(-)(aq))` |
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| 1531. |
Is the reaction, `2Al+3Fe^(2+) hArr 2Al^(3+) + 2Fe` possible ?A. No, because standard oxidation potential of `Al lt Fe`B. Yes , because standard oxidation potential of `Al gt Fe`C. Neither (a) nor (b)D. Data are unpredictable |
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Answer» Correct Answer - B The metal with more `E_(OP)^(@)` is oxidised . |
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| 1532. |
Define electrochemical series. |
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Answer» The arrangement of various electrodes in the decreasing or increasing order of their standard reduction potentials is called electrochemical series. |
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| 1533. |
Find `E_(cell)^(@)` for the cell : `Zn | Zn^(2+)(1M) || Ag^(+)(1M) | Ag` [Given that : `E_(Zn//Zn^(2+))^(@)=0.76" V" , E_(Ag^(+)//Ag)^(@)=0.80" V"`.A. 0.04 VB. `-0.04 V `C. `+1.56 V`D. `-1.56`V |
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Answer» Correct Answer - C `E_("cell")^(@) = E_(OP_(Zn))^(@) + E_(RP_(Ag))^(@) = 0.76 + 0.80 = 1.56` V |
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| 1534. |
How is cell constant calculated from conductance values? |
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Answer» Cell constant= specific conductance/ observed conductance. |
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| 1535. |
Find `E_(cell)^(@)` for the cell : `Zn | Zn^(2+)(1M) || Ag^(+)(1M) | Ag` [Given that : `E_(Zn//Zn^(2+))^(@)=0.76" V" , E_(Ag^(+)//Ag)^(@)=0.80" V"`. |
| Answer» `E_(cell)^(@)=E_(cathode)^(@)-E_(anode)^(@)=E_(Ag^(+)//Ag)^(@)-E_(Zn^(2+)//Zn)^(@)=(0.80)-(-0.76)=1.56" V"` | |
| 1536. |
The `K_(sp)` for AgCl at 298 K is `1.0xx10^(-10)`. Calculate E for `Ag^(+)//Ag` electrode immersed in 1.0 M KCl solution. Given : `E^(@)Ag^(+)//Ag=0.799" V"`. |
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Answer» Calculation of concentration of `Ag^(+)` ions in solution. In this case, `Ag^(+)` ions are deposited as solid AgCl on the electrode. But some `Ag^(+)` ions wil be present in solution and will be in equilibrium with AgCl(s) is solution. `AgCl(s)hArr Ag^(+)(aq)+Cl^(-)(aq)` `K_(sp)=[Ag^(+)][Cl^(-)]" or "[Ag^(+)]=(K_(sp))/([Cl^(-)])` `[Ag^(+)]=(1.0xx10^(-10))/(1.0)=1xx10^(-10)M` Step II. Calculation of E for `Ag^(+)//Ag` electrode. `Ag^(+)(aq)+e^(-) to Ag(s)` According to Nernst equation, `E=E^(@)-(0.0591)/(n)"log"(1)/([Ag^(+)])` `E=0.799-(0.0591)/(1)"log"(1)/(10^(-10))=0.799-0.591=0.208" V"`. |
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| 1537. |
Express the relation among cell constant , resistance of the solution in the cell and conductivity of the solution . How is molar conductivity of a solution related to its conductivity ? |
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Answer» Conductivity (k)`=(1)/(R )xx(l)/(a)("cell constant")` `"Molar condutivity" (Lambda_(m))=(kxx1000)/(C )` |
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| 1538. |
Electrolysis is the process in which electrical energy is converted to chemical energy. In electrolytic cell, oxidation takes place at anode and reduction at cathode. Electrode process depends on the electrode taken for electrolysis. Amount of substance liberated at an electrode is directly propertional to the amount of charge passed through it. The mass of substance liberated at electrode is calculated using the following relation : `m= ("ItE")/(96500)` Here, E represents the equivalent mass and 96500 C is called the Faraday constant. Faraday (96500 C) is the charge of 1 mole electron, i.e., `6.023 xx 10^(23)` electrons, it is used to liberate one gram equivalent of the substance. The passage of current liberates `H_(2)` at cathode and `Cl_(2)` at anode. The solution is :A. Copper chloride in waterB. NaCl in waterC. Ferric chloride in waterD. `AuCl_(3)` in water . |
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Answer» Correct Answer - B Aqueous sol.of NaCl given `H_(2)` at cathode and `Cl_(2)` at anode . |
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| 1539. |
Write the cell reactions which occur in lead storage battery when (i) it is in use (ii) not in use. |
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Answer» (i) When battery is in use i.e., in discharging `Pb(s) +PbO_(2)(s)+4H^(+)(aq)+2SO_(4)^(2-)(aq) to 2PbSO_(4)(s)+2H_(2)O(l)` (ii) When battery is not in use i.e., in charging `2PbSO_(4)(s)+2H_(2)O(l) to Pb(s)+PbO_(2)(s)+4H^(+)(aq)+2SO_(4)^(2-)(aq)` |
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| 1540. |
Electrochemical equivalent of an element isA. `("Atomic mass" xx "Valency")/(96500)`B. `("Atomic mass" xx 96500)/("Valency")`C. `("Atomic mass")/("Valency" xx 96500)`D. `("Valency" xx 96500)/("Atomic mass")` |
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Answer» Correct Answer - C `Z = (E)/(96500) = ("At.mass")/("Valency") xx (1)/(96500)` . |
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| 1541. |
Of the following that cannot be obtained by electrolysis of the aqueous solution of their states is /areA. Ag and MgB. Ag and AlC. Mg and AlD. Cu and Cr. |
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Answer» Correct Answer - C Mg and Al have lower reduction potentials than `H_(2)O` . Hence ,`H_(2)O` is reduced more easily to give `H_(2)` gas at the cathode . |
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| 1542. |
The metal that cannot be obtained by electrolysis of an aqueous solution of its salt isA. CrB. AgC. CaD. Cu |
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Answer» Correct Answer - C out of the given metals, Ca is s-Block metal and is highly electropositive. It cannot be obtained by electrolysis of an aqueous solution of its salt. |
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| 1543. |
In the cell , `Cr(s) | Cr^(3+)(aq) || Cd^(2+)(aq) | Cd(s)`., write down the anodic and cathodic reactions and also overall reaction. |
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Answer» Anode reaction , `Cr(s) to Cr^(3+)(aq)+3e^(-)]xx2` `("Cathodic reaction" : Cd^(2)(aq)+2e^(-) to Cd(s)xx3)/("Overall reaction" : 2Cr+3Cd^(2+)(aq) to2Cr^(3+)(aq)+3Cd(s)` |
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| 1544. |
Why cannot aluminium metal be produced by the electrolysis of aqueous solution of aluminium salt ? |
| Answer» In aqueous solution, `H^(+)` ions will be also formed along formed along with `Al^(3+)` ions. `H^(+)` ions will be released in preference to `Al^(3+)` ionsat the cathode since their discharge potential is less. This means that `Al^(3+)` ions will remain in solution. | |
| 1545. |
Tarnished silver contains Ag2S. Can this tarnish be removed by placing the tarnished ware in an aluminium pan containing an inert electrolyte solution such as NaCl ? Given that the standard reduction potentials for the half reactions are : `Ag2S(s)+2e^(-)to2Ag(s),+S^(2)(aq), E^(@)=-0.71" V"`. `Al^(3+)(aq)+3e^(-) to Al(s), E^(@)=-1.66" V"`. |
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Answer» Yes, the tarnish due to silver sulphate will be removed by placing the tarnished ware in an aluminium pan. Actually, aluminium is is a stronger reducing agent than silver. Therefore, it will reduce silver ions `(Ag^(+))` to metallic silver. It being silvery white in colour will get slowly deposited on the walls of the silver ware and the tarnish will be removed. `Al(s) +3Ag^(+)(aq) to Al^(3+)(aq)+3Ag(s)` Alternatively, `E_(cell)^(@)=E_(cathode)^(@)-E_(anode)^(@)=(-0.71)-(-1.66)=0.95" V"` is positive. The redox reaction is feasible and the tarnish will be removed. |
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| 1546. |
Write the cell reaction taking plce in the cell `CU_((s))|Cu_((aq))^(+2)||Ag _((aq))^(+) |Ag _((s))` |
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Answer» Given cell is `Cu_((s))|Cu _((aq))^(+2)||Ag_((aq))|Ag _((s))` `Cu to Cu ^(+2)+2e^(-)` (Oxidation) `2Ag^(+) + 2e^(-) to 2Ag` (Reduction) |
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| 1547. |
What type of battery is dry cell ? Write overall reaction talking place in dry cell. |
| Answer» Correct Answer - Primary cell. | |
| 1548. |
Best way to prevent rusting of iron is byA. makin g iron cathodeB. putting it in saline waterC. both of theseD. none of these |
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Answer» Correct Answer - A The best way to prevent rusting is b y making iron cathode. |
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| 1549. |
Hos is a galvanic cell rpresented on paper as per IUPAC convention ? Give one example. |
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Answer» Representation of a Galvanic cell: As per IUPAC convention `to` Oxidation half cell represented on the left side. `to` Reduction half cell represented on the right side. `to` Oxidation half cell and reduction half cell are connected by a salt bridge indicated by two vertical parallel lines. `Eg: Cu_((s))|Cu_((aq))^(+2)||Ag_((aq))^(+)|Ag_((s))` |
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| 1550. |
Best way to protect rusting of iron is bt :A. making iron cathodeB. putting it in saline waterC. both of theseD. none of these. |
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Answer» Correct Answer - A (a) Iron will not be able to undergo oxidation when it acts at cathode. |
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