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Grade 12Physical Chemistry

The EMF of a cell corresponding to the reaction Zn(S) + 2H$(aq) ~ Zn2+(0.lM) + H2 (g, 1 atm) is 0.28 volt at 25°c. Calculate the. pH of the solution of the hydrogen electrode. (E: 21Zn ) = -O.76v

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Profile image of diti
6 Years agoGrade 12
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1 Answer

Profile image of Vikas TU
6 Years ago
Hiii 
Zn + 2H+ => Zn2+ + H2
E=0.28V 
Anodic half cell reaction , Zn -2e => Zn2++
Cathodic half cel rection  2H+ + 2e => H2
Ecell = E0 + 0.0529/n *log [H+]^2/[zn2+]
0.28 = 0-(-0.76) + 0.0295 * (2log[H+] + log10) 
0.28 -0.76 =0.0295 *(2log[H+] + 1)
-16.27 -1 = 2log[H+]
log[H+] =-8.6 
-log[H+] =8.6 = pH