Electrochemistry

Electrochemistry

Question

straight a right parenthesis space space Calculate space straight E subscript cell superscript 0 space for space the space following space reaction space at space 298 space straight K colon
2 Al left parenthesis straight s right parenthesis space plus 3 Cu to the power of 2 plus end exponent left parenthesis 0.01 space straight M right parenthesis space rightwards arrow 2 Al to the power of 3 plus end exponent space left parenthesis 0.01 straight M right parenthesis space plus 3 Cu left parenthesis straight s right parenthesis
Given space colon space straight E subscript cell space equals space 1.98 space straight V
straight b right parenthesis space using space the space straight E to the power of 0 space values space of space straight A space and space straight B space predict space which space is space better space for space coating space the space surface space of space iron space left square bracket straight E to the power of 0 left parenthesis Fe to the power of 2 plus end exponent divided by Fe right parenthesis
equals negative 0.44 straight V right square bracket space to space prevent space corrosion space and space why ?
Given space colon space straight E to the power of 0 left parenthesis straight A to the power of 2 plus end exponent divided by straight A right parenthesis space equals space minus 2.37 space colon space straight E to the power of 0 left parenthesis straight B to the power of 2 plus end exponent divided by straight B right parenthesis space equals negative 0.14 space straight V

OR
straight a right parenthesis space The space conductivity space of space 0.001 space mol space straight L to the power of negative 1 end exponent space solution space of space CH subscript 3 COOH space space is space 3.905 space straight x space 10 to the power of negative 5 end exponent space straight S space cm to the power of negative 1 end exponent. space
Calculate space its space molar space conductivty space and space degree space of space dissociation space left parenthesis straight alpha right parenthesis

Given space straight lambda to the power of 0 space left parenthesis straight H to the power of plus right parenthesis space equals 349.6 space straight S space Cm squared space mol to the power of negative 1 end exponent space and space straight lambda to the power of 0 space left parenthesis CH subscript 3 COO to the power of minus right parenthesis space equals space 40.9 space straight S space cm squared space mol to the power of negative 1 end exponent

straight b right parenthesis space Define space electrochemical space cell space what space happen space if space external space potential space applied space
becomes space greater space than space straight E subscript cell superscript 0 space of space electrochemical space cell.

Answer

a)
straight E subscript cell space equals space straight E subscript cell superscript 0 space minus space fraction numerator 0.0591 over denominator straight n end fraction space log space fraction numerator left square bracket Al to the power of 3 plus end exponent right square bracket squared over denominator left square bracket Cu to the power of 2 plus end exponent right square bracket cubed end fraction

straight E subscript cell superscript 0 space equals 1.98 plus fraction numerator 0.0591 over denominator 6 end fraction log space fraction numerator left parenthesis 0.01 right parenthesis squared over denominator left parenthesis 0.01 right parenthesis cubed end fraction

straight E subscript cell superscript 0 space equals space 1.98 space plus fraction numerator 0.0591 over denominator 6 end fraction log space 10 squared

straight E subscript cell superscript 0 space equals space 1.98 space plus fraction numerator 0.0591 over denominator 6 end fraction space straight x space 2 space straight x space log space 10
straight E subscript cell superscript 0 space equals space 1.98 space plus fraction numerator 0.0591 over denominator 6 end fraction space straight x space 2
straight E subscript cell superscript 0 space equals space 1.98 space straight V space plus 0.0197 straight V
straight E subscript cell superscript 0 space equals 1.9997 space straight V
b) A is better for coating the surface of the iron because its E0  value is more negative.

Or
a) straight capital lambda subscript straight m space equals fraction numerator space straight k space straight x space 1000 over denominator straight C end fraction
space equals fraction numerator 3.905 space straight x space 10 to the power of negative 5 end exponent space straight x space 1000 over denominator 0.001 end fraction
equals 39.05 space straight S space cm squared divided by mol

CH subscript 3 COOH space rightwards arrow CH subscript 3 COO to the power of minus space plus straight H to the power of plus
straight capital lambda to the power of 0 space CH subscript 3 COOH space equals space straight lambda to the power of 0 CH subscript 3 COO to the power of minus space plus space straight lambda to the power of 0 straight H to the power of plus

equals space 409 plus 349.6
straight capital lambda to the power of 0 CH subscript 3 COOH space equals 390.5 space straight S space cm squared divided by mol
straight alpha space equals space fraction numerator straight capital lambda subscript straight m over denominator straight capital lambda subscript straight m superscript 0 end fraction
equals 39.05 divided by 390.5 equals 0.1
b) A device used for the production of electricity from energy released during the spontaneous chemical reaction and the use of electrical energy to bring about a chemical change. The reaction gets reversed /  It starts acting as an electrolytic cell & vice – verse.

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