Calculate the voltage (E) of a concentration cell constructed with the Cl- concentration difference between sea water and river water at 25ËC. Assume that the Cl- concentration (due to dissolved NaCl) of sea water is 35 g/L and that of river water is 1.0 mg/L.

Respuesta :

Answer:

The voltage is [tex]E = 0.268V[/tex]

Explanation:

Since the main source of [tex]Na Cl[/tex] is the sea water then

   The equation for the reaction  [tex]Cl^{-}[/tex]  in sea water would be

              [tex]Cl^- ----->\frac{1}{2}Cl_2 + e^-[/tex]

that is the ion would form a molecule [tex]Cl_2[/tex] and then release an electron

For river water

               [tex]\frac{1}{2}Cl_2 + e^- -----> Cl^-[/tex]

I.e the molecule would gain an electron and forms an ion

Now  [tex]Cl^-[/tex] acts as reactant for seawater reaction and product for river water

    The voltage of the concentration cell at initial stage is [tex]E_0 = 0[/tex]

Now at  the voltage for the cell with [tex]Cl^-[/tex] concentration difference between sea water and river water is mathematical denoted as

                [tex]E = E_0 - \frac{0.059}{n_e} log\frac{[Cl^-]_{product}}{[Cl^-]_{reactant}}[/tex]

Where [tex]n_e[/tex] is the number of electron = 1

So substituting values we have

              [tex]E = 0 - \frac{0.059}{1} log\frac{1.0*10^{-3}}{35}[/tex]

   Removing the negative sign

              [tex]E = \frac{0.059}{1} log\frac{35}{1.0*10^{-3}}[/tex]

                  [tex]E = 0.268V[/tex]

                 

                   

             

Answer:

the voltage (E) of a concentration cell constructed is  0.268V

Explanation:

Chlorine concentration cell

   Pt, Cl₂ / Cl⁻    //    Cl⁻, Cl₂ , Pt

   sea water             River water

[tex]Cl^- \rightarrow \frac{1}{2} Cl_2+e^-\\\\\frac{1}{2} Cl_2+e^- \rightarrow Cl^-[/tex]

Therefore,

It is concentration cell [tex]E^0 = 0[/tex]

[tex]E = E^0-\frac{0.059}{n} log\frac{[Cl^-]_{product}}{[Cl^-]_{rreactant}}[/tex]

[tex]Q = \frac{[Product]}{[Reactant]}[/tex]

[tex]E = Q - \frac{0.059}{1} log\frac{[Cl^-]_{riverwater}}{[Cl^-]_{seawater}}[/tex]

⇒[tex]0.059log\frac{[Cl^-]_{seawater}}{[Cl^-]_{riverwater}}[/tex]

[tex][Cl^-]_{seawater} = \frac{35}{35.5}[/tex]

[tex][Cl^-]_{riverwater}=\frac{10^-^3}{35.5}[/tex]

⇒ 0.059 log (35 × 10³)

E = 0.268V

Hence, the voltage (E) of a concentration cell constructed is  0.268V