Home
Class 12
CHEMISTRY
The emf of a cell corresponding to the r...

The emf of a cell corresponding to the reaction
`Zn +2H^(+)(aq) rarr Zn^(2+) (0.1M) +H_(2)(g) 1` atm is `0.28` volt at `25^(@)C`. Calculate the `pH` of the solution at the hydrogen electrode.
`E_(Zn^(2+)//Zn)^(@) =- 0.76` volt and `E_(H^(+)//H_(2))^(@) = 0`

Text Solution

Verified by Experts

The cell reaction is
`Zn_((s))+2H_((aq))^(+) Leftrightarrow (0.10M)+H_(2(g))+"1 atm"`
From questions `E_(Zn^(+2)//Zn)^(0)=0.75" volt"`
`E^(0)=E_(Zn//Zn^(++))+E_(H^(+)//H_(2))^(0)`
=+0.76V+0.0V
From Nernst equation
`E_("cell")=E_("cell")^(0)-(0.052)/(n) log ([Zn^(++)].P_(H_(2)))/([H^(+)]^(2))`
`0.2 =E_("cell")^(0) -(0.0592)/(2) log (0.1)/([H^(2)]^(2)) xx 1`
`0.28=0.76-(0.0592)/(2) log"" (0.1)/([H^(+)]^(2))`
`or, log""(0.1)/([H^(+)]^(2))=2 xx ((0.76-0.28))/(0.0592)`
`log_(0.1)-2log[H^(+)]=16.216`
`or, 2pH =17.216`
`pH=8.608`
Promotional Banner

Topper's Solved these Questions

  • ELECTROCHEMISTRY

    FIITJEE|Exercise Solved Problems (Subjective)|25 Videos

  • ELECTROCHEMISTRY

    FIITJEE|Exercise Solved Problems (Objective)|41 Videos

  • CONCEPT OF ACIDS AND BASES

    FIITJEE|Exercise SINGLE INTEGER ANSWER TYPE QUESTIONS|4 Videos

  • ELECTROPHILIC AROMATIC SUBSTITUTION

    FIITJEE|Exercise NUMERICAL BASED QUESTIONS INDICATED BY DIGITAL INTERGER|1 Videos

Similar Questions

Explore conceptually related problems

The emf of a cell corresponding to the reaction. Zn(s)+ 2H^(+)(aq)rightarrow Zn^(2+)(0.1M)+H_(2) (g,1atm) is 0.28 V at 25^(@) C . Calculate pH of the solution.

Emf of a cell corresponding to the reaction:- Zn(s) +2H^(+) (aq) rarr Zn^(2+)(aq) [0.1M] +H_(2)(g) [1.0atm] is 0.49V at 25^(@)C, E_(Zn^(2+)//Zn)^(@) = - 0.76 V . The pH of solution in cathode chamber is.

The emf of a cell corresponding to the following reaction is 0.0199 V at 298 K. Zn(s) + 2H^(+)(aq) rightarrow Zn^(2+)(0.1M) + H_(2)(g)(E_(Zn//Zn^(2+))^(@) = 0.76V The approximate pH of the solution at the electrode where hydrogen is being produced is [pH_(2) = 1 atm] :

For the cell Zn(s) + 2H^(+)(aq) rightarow Zn^(2+)(aq) + H_(2)(g) , E^(@) = 0.76 V Which change will increase the voltage of the cell?

The e.m.f. of a cell corresponding to the reaction : Zn_((s))+2H_((aq.))^(+) rarr underset((0.1 M))(Zn^(2+))+underset((1 atm))(H_(2(g)) is 0.28 V at 25^(@)C and E_(Zn//Zn^(2+))^(@) = 0.76V . (i) Write half cell reactions. (ii) Calculate pH of the solution at H electrode.