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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.
| 701. |
The EMF of a cell is related to the equilibrium constant of the cell reaction asA. `ln K_(c) = (nFE_("cell")^(@))/(RT)`B. `K_(c) = (nFE_("cell")^(@))/(RT)`C. `E_("cell")^(@) = (RT)/(nF)"ln" K_(c)`D. `K_(c) = (RT)/(nF) "ln" E_("cell")^(@)` |
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Answer» Correct Answer - A `E_("cell")^(@) = (RT)/(nF) "ln" K_(c)` or ln `K_(c) = (nF E_("cell")^(@))/(RT)`. |
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| 702. |
In a calomel electrode glass tube is filled withA. paste of calomel in Hg and saturated KCl solutionB. paste of calomel in HgC. paste of `PbCl_(2)` in HgD. saturated KCl and `PbCl_(2)` |
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Answer» Correct Answer - A In calmel electrode , a paste of `Hg_(2)Cl_(2)` (calomel) in Hg and saturated KCl solution . |
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| 703. |
How many moles of Pr may be deposited on the cathode when 0.80F of electricity is passed through 1.0M solution of `Pt^(4+)`?A. 0.1 molB. 0.2 molC. 0.4 molD. 0.6 mol |
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Answer» Correct Answer - B `Pt^(4+) + 4e^(-) to Pt` 4 moles of electricity or 4 F of electricity is required to deposit 1 mole of Pt. 0.80 F of electricity will deposit `1/4xx0.80` =0.20 mol |
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| 704. |
The amount of chlorine evolved by passing 2 A of current in an aqueous solution of NaCI for 30 minutes isA. 2.64 gB. 1.32 gC. 3.62 gD. 4.22 g |
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Answer» Correct Answer - B NaCl `to Na^+ + Cl^-` `2Cl^(-) + 2e^(-) to Cl_2` Q = I x t = 2 x 30 x 60 = 3600 Coulombs 2 x 96500 Coulombs produce = 71 g of `Cl_2` 3600 Coulombs will produce =`71/(2xx96500)xx3600` =1.32 g of `Cl_2` |
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| 705. |
CALOMEL ELECTRODEA. its potential is arbitrarily fixedB. its potential is exactly known with respect to a standardC. the effects of temperature on e.m.f. of electrode is negligibleD. both a and c |
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Answer» Correct Answer - B The calomel electrode is used as a reference electrode because its potential fixed and known . |
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| 706. |
The cell constant of a conductivity cellA. chagnes with chagne of electroyteB. Changes with chagne of concentration of electrolyteC. chagnes with temperature of electrolyteD. remains cosntant for a cell |
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Answer» Cell cosntant is defind as the ratio of length of object and area of cross section. `G=(1)/(A)` Since, l and A remain constant for any particulr object hence value of cell constant always remains constant. |
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| 707. |
In electroplating, the article to be electroplated serves areA. CathodeB. ElectrolyteC. AnodeD. Conductor |
| Answer» Correct Answer - A | |
| 708. |
In a hydrogen-oxygen fuel cell, combustion of hydrogen occurs to :A. produce high purity waterB. create potential difference between two electrodesC. generate heatD. remove adsorbed oxygen from electron surface. |
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Answer» Correct Answer - B (b) Combustion of `H_(2)` (g) creates potential difference between the electrodes. |
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| 709. |
In `H_(2) -O_(2)` fuel cell , combustion of `H_(2)` occurs toA. generate heatB. create P.D. between two electrodes .C. produce high purity waterD. absorbs heat |
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Answer» Correct Answer - B It is a fact for fuel cell . |
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| 710. |
The standard potentials of some electrodes are as follows. Arrange the metals in an increasing order of their reductiong power. `1)K^(+)//K=-2.93V" "2)Ag^(+)//Ag =0.80V" "3) Cu^(2+)//Cu=0.34V` `4)Mg^(2+)//Mg =-2.37V" "5)Cr^(3+)//Cr =-0.74C" "6)Fe^(+)//Fe =-0.44V` |
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Answer» Given `{:(E_(0)"of cell" K ^(+)//K , =-2.93V),(Ag^(+)//Ag, =0.80V),(Cu^(+2)//Cu, =0.34V):}{:(Mg^(+2) //Mg , =-2.37V),(Cr^(+3)//Cr, =-0.74V),(Fe^(+2)//Fe, =-0.44V):}` Lower the reduction potential values indicates high reducing power and high value indicates the high oxidising power. So, increasing order of the given cells reducing power is `Ag lt Cu lt Fe lt Cr lt Mg lt K.` |
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| 711. |
The calomel electrode is reversible with repect to :A. `Hg`B. `H^(+)`C. `Hg^(2+)`D. `Cl^(-)` |
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Answer» Correct Answer - D Calomel electrode reaction, `1//2Hg_(2)Cl_(2(s))+e^(-)hArr Hg_((l))+Cl_((aq.))^(-)` Calomel electode. `E_(Cl^(-)//Hg_(2)Cl_(2)//Hg)` `E_(Cl^(-)//Hg_(2)Cl_(2)//Hg) + (2.303RT)/(F)log[Cl^(-)]` Thus calomel electrdoe funcations as the reversible chloride electrode. |
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| 712. |
Which of the following is false for normal hydrogen electrode ?A. the temperature is 298 KB. the concentration of `H^(+)` ions in its solution is 1 MC. the hydrogen gas pressure is 2 atmospheresD. an electrode to Pt , coated with platinum black is used |
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Answer» Correct Answer - C In NHE the hydrogen gas at 1 atm pressure is used . |
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| 713. |
During the working of a galvanic cell and with the passage of time.A. Spontaneity of the cell reaction decreases, `E_(cell)` decreasesB. Reaction quotient `Q` decreases, `E_(cell)` increasesC. Reaction quotient `Q` increases, `E_(cell)` decreasesD. At equilibrium, `Q=K_(eq),E_(cell)=0` |
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Answer» Correct Answer - a,c,d During the working of a galvanic cell, it reaches equilibrium from its standard conditions. `implies Quarr` to reach `K_(eq),E_(cell)darr` Reaction becomes less spontaneous as `E_(cell)darr`. |
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| 714. |
When during electrolusis of a solution of `AgNO_3, 9650` coulmbs of charge pass through the electroplationg bath, the mass of silver deposited on the cathode will be:A. 108 gB. 10.8 gC. 1.08 gD. 216 g |
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Answer» Correct Answer - B `Ag^+ + underset"1 F"(e^(-)) to underset"108 g"(Ag )` Amount of Ag deposited by 9650 C `=108/96500xx9650`=10.8 g |
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| 715. |
In a hydrogen-oxygen fuel cell, combustion of hydrogen occurs to :A. remove adsorbed oxygen from electrode surfacesB. create potential difference between the two electrodesC. produce high purity waterD. generate heat |
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Answer» Correct Answer - B `{:(2H_(2)+4OH_((aq.))^(-)rarr4H_(2)O_((l))+4e),(O_(2(g))+2H_(2)O_((l))+4erarr4OH_((aq.))^(-)):}/(2H_(2)+O_(2(g))rarr2H_(2)O_(l),E_(cell)^(@)=+ve)` Fuel cell involves direct conversion of chemical energy to electrical energy. |
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| 716. |
The difference between the electrode potentials of two electrons when no current is drawn through the cell is called:A. cell potentialB. cell emfC. potential differenceD. cell voltage |
| Answer» Correct Answer - B | |
| 717. |
The calomel electrode is reversible with repect to :A. `Cl^(-)` ioinsB. `H^(+)` ionsC. both `H^(+)` and `Cl^(-)` ionsD. neither , it is irreversible |
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Answer» Correct Answer - A `Hg_(2) Cl_(2) + 2e^(-) hArr 2 Hg + 2 Cl^(-)` |
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| 718. |
Pairs of electrodes and their corresponding standard electrode potentials are given. Arrange the cells constructed by these electrodes in increasing order of emf values (1) Electrode `rarr A, E^(@) = - 2.92 V` and Electrode `rarr B, E^(@) = - 2.71 V` (2) Electrode `rarr C, E^(@) = - 0.760 V` and Electrode `rarr D, E^(@) = -0.44 V` (3) Electrode `rarr B, E^(@) = - 2.71` and Electrode `rarr D, E^(@) = -0.44 V` (4) Electrode `rarr A, E^(2) = -2.92 V` and Electrode `rarr C, E^(@) = -0.76 V`A. 2 1 4 3B. 1 2 4 3C. 2 4 1 3D. 2 4 3 1 |
| Answer» `{:((i), "Electrode" - A"," E^(@) = - 2.92 V and ),(,"Electrode " - B"," E^(@) = -2.71 V),((ii),"Electrode " - C"," E^(@) = - 0.760 V and),(,"Electrode" - D "," E^(@) = -0.44 V),((iii),"Electrode" - B"," E^(@) = -2.71 V and),(,"Electrode " - D"," E^(@) = -0.44 V),((iv),"Electrode " - A "," E^(@) = -2.92 V and),(,"Electrode " - C"," E^(@) = -0.76 V):}` | |
| 719. |
The quantity of charge required to obtain one mole of aluminium from `Al_(2)0_(3)` isA. 1FB. 6FC. 3FD. 2F |
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Answer» The quantity of charge required to obtain one mole of aluminium from `Al_(2)O_(3)` is equal to number of electron required to convert `Al_(2)O_(3)` to Al. `Al^(3+)(aq)overset(+3e)rarrAl(s)` Hence, total 3F is required |
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| 720. |
Which of the following changes will cause the free energy of a cell reaction to decrease ? `Zn|ZnSO_(4)(aq)(x_(1)M)||HCl(aq)(x_(2)M)|H_(2)(g),Pt`.A. Increase in the volume of `HCl` solution from `100mL` to` 200mL`B. Increase in the pressure of hydrogen from `1 atm ` to `2 atm`C. Increase in molarity `x_(2)` from `0.1 ` to `1M`D. Increase in molarity `x_(1)` from `1M` to `0.1M`. |
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Answer» Correct Answer - c,d `Zn|Zn^(2+)(x_(1)M)||H^(o+))|H_(2)(g),Pt` Free energy to decrease `implies` cell is more spontaneous `(E_(cell)uarr)` `Zn+2H^(o+)(x_(2)M) rarr Zn^(2+)(x_(1)M)+H_(2(g))` `implies E_(cell)=E^(c-)._(cell)-(0.059)/(2) log .([Zn^(2+)]p_(H_(2)))/([H^(o+)]^(2))` `DeltaG=-ve or E_(cell)=+ve` `c.` When `x_(2)(0.1M)` changed to `1M`. `d.` When `x_(1)(1M)` changed to `0.1M`. |
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| 721. |
When during electrolusis of a solution of `AgNO_3, 9650` coulmbs of charge pass through the electroplationg bath, the mass of silver deposited on the cathode will be:A. `1.08 g`B. `10.8 g`C. `21.6 g`D. `108 g` |
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Answer» Correct Answer - B `w = (E . Q)/(96500) = (108 xx 9650)/(96500) = 10.8 g` |
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| 722. |
Which of the following statement is not correct about an inert electrode in a cell?A. It does not participate in the cell reaction.B. It provides surface either for oxidation or for reduction reaction.C. It is provides surface for conduction of electrons.D. It provides surface for redox reaction. |
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Answer» Correct Answer - D (d) An inert electrode provides surface for oxidation or reduction reaction and not for redox reaction. |
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| 723. |
The standard Hydrogen electrode in which the inert metal used isA. PbB. PdC. PtD. Ni |
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Answer» Correct Answer - A Pt in an inert metal . |
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| 724. |
The difference between the electrode potentials of two electrodes when no current is drawn through the cell is called ___________.(i) Cell potential(ii) Cell emf(iii) Potential difference(iv) Cell voltage |
| Answer» (ii) Cell emf | |
| 725. |
Which of the following statement is not correct about an inert electrode in a cell?A. It does n ot participate in the cell reactionB. It provides surface either for oxidation or for reduction reactionC. It provides surface for conduction of electronsD. It provides surface for redox reaction. |
| Answer» An inert electrode in a cell provide surface of either oxidation or for reduction reaction by conduction of electrons through its surface but does not participate in the cell it does not provide surface for redox reaction. | |
| 726. |
Which of the following is the most powerful reducing agent ?A. `F^(c-)`B. `Cl^(c-)`C. `Br^(c-)`D. `I^(c-)` |
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Answer» Correct Answer - d `I^(c-)` has the highest tendency to get oxidized`(2I^(c-) rarr I_(2)+2e^(-))(` Refer electrochemical series `)` and thus is the most powerful reducing agent. |
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| 727. |
The strongest oxidizing agent among the species In3+ (E0 = – 1.34 V), Au3+(E0 = 1.4 V), Hg2+ (E0 = 0.86 V), Cr3+ (E0 = – 0.74 V) is :(a) Cr3+ (b) Au3+ (c) Hg2+(d) In3+ |
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Answer» Option : (b) Au3+ |
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| 728. |
For the concentration cell `Pt(H_(2)-p_(1))|H^(+)(0.5M)|Pt(H_(2)-P_(2))` the cell reaction will be spontaneous ifA. `p_(1)=p_(2)`B. `p_(1)gtp_(2)`C. `p_(2)gtp_(1)`D. None of these |
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Answer» Correct Answer - B `Pt(H_(2)-p_(1))|H^(+)(0.5M)|Pt(H_(2)-p_(2))` it is a concentration cell reversible w.r.t. cation `H_(2)(p_(1))rarr2H^(+)2e^(-)` `2H^(+)+2e^(-)rarrH_(2)(p_(2))` `H_(2)(p_(1))rarrH_(2)(p_(2))` `E_("cell")=-(0.591)/( 2)"log"(p_(2))/(p_(1))` `=(0.0591)/(5) "log"(p_(1))/(p_(2))` `E_("cell")gt0` if `p_(1)gtp_(2)` |
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| 729. |
Consider the cell `:` `Pt|H_(2)(p_(1)atm)|H^(o+)(x_(1)M) || H^(o+)(x_(2)M)|H_(2)(p_(2)atm)Pt`. The cell reaction be spontaneous ifA. `p_(1)=p_(2)` and `x_(1) lt x_(2)`B. `p_(1)=p_(2)` and `x_(1) lt x_(2)`C. `x_(1)=x_(2)` and `p_(1) gt p_(2)`D. `x_(1)=x_(2)` and `p_(1)ltp_(2)` |
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Answer» Correct Answer - b,c `E_(red)=-0.059[pH+(logpH_(2))/(2)]` `implies E_(cell)=0.059[pH_(a)-pH_(c)+(1)/(2)log.((pH_(2))_(a))/((pH_(2))_(c))]V` `E_(cell)gt0`, when `p_(1)=p_(2)` and `x_(1)ltx_(2)` or when `x_(1)=x_(2)` and `p_(1)gtp_(2)` |
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| 730. |
The strongest oxidizing agent among the following isA. `K_(2)Cr_(2)O_(7)`B. `MnO_(2)`C. `KMnO_(4)`D. `Cl_(2)` |
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Answer» Correct Answer - c `E^(c-)._(Cr_(2)O_(7)^(2-)|Cr^(3+))=1.33V,E^(c-)._(MnO_(2)|Mn^(2+))=1.23V,` `E^(c-)._(MnO_(4)^(c-)|Mn^(2+))=1.51V,e^(C-)._(Cl_(2)|Cl^(c-))=1.36V,` `:. E^(c-)._(MnO_(4)^(c-)|Mn^(2+))` is highest , `KMnO_(4)` is the strongest oxidizing agent. |
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| 731. |
The standard `EMF` of a galvanic cell involving cell reaction with `n=2` is found to be `0.295 V` at `25^(@)C` . The equilibrium constant of the reaction would beA. `1 xx 10^(-10)`B. `29.5 xx 10^(-2)`C. `10`D. `1 xx 10^(10)` |
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Answer» Correct Answer - D `E_(cell)^(@) = (0.059)/(n)logK_(c)` `0.295 = (0.059)/(2)logK_(c)` `K_(c) = 1 xx 10^(10)` |
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| 732. |
An electrochemical cell an behave like an electrolytic cell whenA. `E_(cell)=0`B. `E_(cell) gt E_("ext")`C. `E_("ext") gt E_(cell)`D. `E_(cell) gt E_("ext")` |
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Answer» Correct Answer - C (c ) Electrochemical cell behaves as an electrolytic cell in case external potential `(E_("ext"))` is more than `E_(cell)`. |
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| 733. |
Which of the following statement is not correct about an inert electrode in a cell?(i) It does not participate in the cell reaction.(ii) It provides surface either for oxidation or for reduction reaction.(iii) It provides surface for conduction of electrons.(iv) It provides surface for redox reaction. |
| Answer» (iv) It provides surface for redox reaction. | |
| 734. |
Using the data given below: `E_(Cr_(2)O_(7)^(2-)|Cr^(3+))^(@)=1.33V E_(Cl_(2)|Cl^(-))^(@)=1.36V` `E_(MnO_(4)^(-)|Mn^(2+))^(@)=1.51V E_(Cr^(3+)|Cr)=-0.74V` Find the most stable oxidised species.A. `Cr^(3+)`B. `MnO_(4)^(-)`C. `Cr_(2)O_(7)^(2-)`D. `Mn^(2+)` |
| Answer» `E_(Cr^(3+)//Cr)^(@)` has most -ve value equal to -0.74 among given four choices. So `Cr^(3+)` is the most stable oxidised species. | |
| 735. |
Consider the cell `:` `Pt|H_(2)(p_(1)atm)|H^(o+)(x_(1)M) || H^(o+)(x_(2)M)|H_(2)(p_(2)atm)Pt`. The cell reaction be spontaneous ifA. `p_(1)=p_(2)`B. `p_(1)gtp_(2)`C. `p_(2)gtp_(1)`D. `p_(1)=1 atm` |
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Answer» Correct Answer - b Cell is spontaneous when `p_(1)(` anode `)gtp_(2)(` cathode `)` `E_(cell)=0.05[pH_(a)-pH_(c)+(1)/(2)log.((pH_(2))_(a))/((pH_(2))_(c))]` `=0.059[0-0+(1)/(2)log.(p_(1))/(p_(2))]` Thus, `E_(cell)gt0` if `p_(1)gtp_(2)` |
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| 736. |
If all species are in their standard states, which of the following is the strongest oxidizing agent ?A. `Br^(c-)`B. `Zn^(2+)`C. `CO^(3+)`D. `Fe^(2+)` |
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Answer» Correct Answer - c Refer to electrochemical series. |
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| 737. |
An electrochemical cell can behave like an electrolytic cell when ____________.(i) Ecell = 0(ii) Ecell > Eext(iii) Eext > Ecell(iv) Ecell = Eext |
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Answer» (iii) Eext > Ecell |
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| 738. |
For `Pt(H_(2))|H_(2)O` , reduction potential at `298 K` and `1 atm` is `:`A. `-0.23V`B. `-0.41V`C. `0.41V`D. `0.00V` |
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Answer» Correct Answer - b `pH ` of `H_(2)O=7` `:. E_(2H^(o+)|H_(2))=-0.059pH=-0.059xx7=-0.41V` |
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| 739. |
The standard `EMF` of a galvanic cell involving cell reaction with `n=2` is found to be `0.295 V` at `25^(@)C` . The equilibrium constant of the reaction would beA. `4.0 xx 10^(12)`B. `1.0xx10^(2)`C. `1.0 xx 10^(10)`D. `2.0xx10^(11)` |
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Answer» Correct Answer - c `log K_(eq)=(n_(cell)E^(c-)._(cell))/(0.059)=(2xx0.295)/(0.059)=10` `:. K_(eq)=10^(10)` |
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| 740. |
Use the data given in Q.8 and find out the most stable ion in its reduced form.A. `Cl^(-)`B. `Cr^(3+)`C. `Cr`D. `Mn^(2+)` |
| Answer» `E_(MnO_(4)^(2+))^(@)` has +ve value equal to 1.51V which is highest among given four choices. So `Mn^(2+)` is most stable ion in its reduced form. | |
| 741. |
Which of the statements about solutions of electrolytes is not correct?(i) Conductivity of solution depends upon size of ions.(ii) Conductivity depends upon viscosiy of solution.(iii) Conductivity does not depend upon solvation of ions present in solution.(iv) Conductivity of solution increases with temperature. |
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Answer» (iii) Conductivity does not depend upon solvation of ions present in solution. |
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| 742. |
Use the data of Q.8 and find out the most stable oxidised species.(i) Cr3+(ii) MnO4–(iii) Cr2O72–(iv) Mn2+ |
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Answer» The correct answer is (i) Cr3+ |
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| 743. |
The correct order of reactivity of `K,Mg,Zn` and `Cu` with water according to the electrochemical series isA. `KgtMggtZngtCu`B. `MggtZngtCugtK`C. `KgtZngtMggtCu`D. `CugtZngtMggtK` |
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Answer» Correct Answer - a Refer to electrochemical series. |
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| 744. |
Using the data given below find out the strongest reducing agent. |
| Answer» The correct answer is (ii) Cr | |
| 745. |
In a cell that utilises the reaction. `Zn(s) +2H^(+)(aq) rarr Zn^(2+) (aq) +H_(2)(s)` addition of `H_(2)SO_(4)` to cathode compartement, will: (1) increase the `E_(Cell)` and shift equilibrium to the right (2) lower the `E_(cell)` and shift equilibrium to the right (3) lower the `E_(cell)` and shift equilibrium to the left (4) increase the `E_(cell)` and shift equilibrium to the left |
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Answer» Correct Answer - A `E_(cell) = E_(cell)^(@) - (0.059)/(2)log.(1)/([H^(+)]^(2))` On adding `H_(2)SP_(4),[H^(+)]` will increase therefore `E_(cell)` will also increase and the equilibrium will shift towards right. |
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| 746. |
Use the data given in Q.8 and find out the most stable ion in its reduced form.(i) Cl–(ii) Cr3+(iii) Cr(iv) Mn2+ |
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Answer» The correct answer is (iv) Mn2+ |
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| 747. |
Using the data given in Q.8 find out in which option the order of reducing power is correct.(i) Cr3+ < Cl– < Mn2+ < Cr(ii) Mn2+ < Cl– < Cr3+ < Cr(iii) Cr3+ < Cl– < Cr2O72– < MnO4–(iv) Mn2+ < Cr3+ < Cl– < Cr |
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Answer» (ii) Mn2+ < Cl– < Cr3+ < Cr |
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| 748. |
Assertion:The electrical resistance of any object decrease with increase in its length. Reason: Electrical resistance of any object increases with increase in its area of cross-section.A. If both assertion and reason are true and reason is the correct explanation of assertion .B. If both assertion and reason are true but reason is not the correct explanation of assertion .C. If assertion is true but reason is false .D. If both assertion and reason are false . |
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Answer» Correct Answer - D `R prop l/A`, hence it increases with increase in the length of the object and decreases with increase in its area of cross -section |
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| 749. |
Use the data in Q.8 and find out which of the following is the strongest oxidising agent.A. `Cl^(-)`B. `Mn^(2+)`C. `MnO_(4)^(-)`D. `Cr^(3+)` |
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Answer» Correct Answer - C (c ) `MnO_(4)^(-)` is the stronger oxidising agent because `E^(Ï´)` value is maximum in this case. In other words,the negative `E^(Ï´)` value is minimum in this case. |
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| 750. |
Use the data given in Q.8 and find out which of the following is the strongest oxidising agent.(i) Cl–(ii) Mn2+(iii) MnO4–(iv) Cr3+ |
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Answer» The correct answer is (iii) MnO4– |
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