Home
Class 12
CHEMISTRY
A cell is constructed by dipping a zinc ...

A cell is constructed by dipping a zinc rod in 0.1 M zinc nitrate solution and a lead rod in 0.2 M lead nitrate solution.
`E_(Pb^(2+)//Pb)^(Theta) = -0.13 V and E_(Zn^(2+)//Zn)^(Theta) = -0.76V`
(i) Write the spontaneous cell reaction.
(ii) Calculate standard emf and emf of the cell.

Text Solution

Verified by Experts

(i) `Zn^(2+) +2e^(-) to Zn, E^(Theta) = -0.76V`
`Pb^(2+) +2e^(-) to Pb, E^(Theta) = -0.13V`
From the standard electrode potentials, it is evident that the electrons will be released at the zinc electrode and gained at the lead electrode. Therefore, the spontaneous cell reaction is :
`Zn +Pb^(2+) to Zn^(2+) +Pb`
or cell representation is : `Zn//Zn^(2+)"||"Pb^(2+)//Pb`
(ii) `E_("cell")^(Theta)=E_("cathode")^(Theta)-E_("anode")^(Theta)`
`= -0.13V-(-0.76V)=0.63V`
`E_("cell")=E_("cell")^(Theta)-(0.0591)/(n)"log"(["Products"])/(["Reactants"])`
`=0.63-(0.0591)/(2)"log"([Zn^(2+)])/([Pb^(2+)])`
`=0.63 -(0.0591)/(2)"log"([0.1])/([0.2])`
`=0.63-0.0295 log ((1)/(2))V`
`=0.63-0.0295[log 1-log 2]V`
`=0.63 -0.0295 [0-0.3010]`
`=0.63+0.03=0.66V`
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • ELECTROCHEMISTRY

    ICSE|Exercise ISC EXAMINATION QUESTIONS (PART-II Descriptive Questions) |11 Videos

  • DISTINCTION BETWEEN PAIRS OF COMPOUNDS

    ICSE|Exercise QUESTIONS |155 Videos

  • GENERAL PRINCIPLES AND PROCESSES OF ISOLATION OF ELEMENTS

    ICSE|Exercise EXERCISE (PART-I ( OBJECTIVE QUESTIONS )) (Fill in the blanks)|60 Videos

Similar Questions

Explore conceptually related problems

(a) A cell is prepared by dipping a zinc rod in 1M zinc sulphate solution and a silver electrode in 1M silver nitrate solution. The standard electrode potential given : E^(@)Zn_(2+1//Zn) = -0.76V, E^(@)A_(g+//)A_(g) = +0.80V What is the effect of increase in concentration of Zn^(2+) " on the " E_(cell) ? (b) Write the products of electrolysis of aqueous solution of NaCI with platinum electrodes. (c) Calculate e.m.f. of the following cell at 298 K: "Ni(s)"//"Ni"^(2+)(0.01M)////"Cu"^(2+)(0.1M)//"Cu(s)" ["Given"E_(Ni2+//Ni)^(@) = -0.025 V E_(Cu2+//Cu)^(@) = +0.34V] Write the overall cell reaction.

Explain the following : Zinc displaces hydrogen from acid solution. E_(Zn^(2+)//Zn)^(Theta)= -0.76V

Why blue colour of CuSO_(4) solution gets discharged when zinc rod is dipped in it ? Given, E_(Cu^(+2)//Cu)^(@)=0.34 V and E_(Zn^(+2)//Zn)^(@)=-0.76V

A cell is prepared by dipping copper rod in 1 M copper sulphate solution and zinc rod in 1 M zinc sulphate solution. The standard reduction potential of copper and zin c are 0.34 V and - 0.76 V respectively. (i) What will be the cell reaction ? (ii) What will be the standard electromotive force of the cell ? (iii) Which electrode will be positive ?

Calculate the equilibrium constant for the reaction: Cd^(2+) (aq) +Zn(s) hArr Zn^(2+) (aq) +Cd (s) If E_(Cd^(2+)//Cd)^(Theta) = -0.403V E_(Zn^(2+)//Zn)^(Theta) = -0.763 V

Why zinc coating protects iron more effectively than tin coating ? Given E_(Zn^(2+)//Zn)^(Theta)= -0.76V , E_(Sn^(2+)//Sn)^(Theta)= -0.14V, E_(Fe^(2+)//Fe)^(Theta)= -0.44V

Can a solution of 1 M ZnSO_(4) be stored in a vessel made of copper ? Given that E_(Zn^(+2)//Zn)^(@) =-0.76V and E_(Cu^(+2)//Cu)^(@)=0.34 V

Calculate the e.m.f. of the cell Zn//Zn^(2+) (0.1M) "||" Cu^(2+) (0.01M) "|"Cu E_(Zn^(2+)//Zn)^(Theta)= -0.76 " V and "E_(Cu^(2+)//Cu)^(Theta)=0.34V

For the given cell arrangement identify incorrect statement given E^@_(Cu^(2+)//Cu) = 0.34V & E^@_(Zn^(2+)//Zn) = -0.76V

Calculate the maximum work that can be obtained from the given electrochemical cell constructed with two metals M and N. [E_(M^(2+)//M)^(Theta)= -0.76V, E_(N^(2+)//N)^(Theta) = 0.34V]

Home
Profile