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Predict whether zinc nd silver react with 1 M sulphuric acid to give out hydrogen gas or not. Given that the standard reduction potential of zinc and silver are -0.76 volt and 0.80 volt respectively. |
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Answer» Solution :(a) To predict reaction of zinc with SULPHURIC acid: if it reacts, the following reaction should take place: `Zn+H_(2)SO_(4) to ZnSO_(4)+H_(2),"i.e.,"Zn+2H^(+)TOZN^(2+)+H_(2)` By convention, the cell will be represented as: `Zn|Zn^(2+)||H^(+)|H_(2)`. Std. EMF of the cell `(E_(cell)^(@))=["Std. redn. pot. of R.H.S. electrode"]-["Std. redn. pot. of L.H.S. electrode"]=0-(-0.76)=+0.76` volt. THUS, the EMF of the cell comes out to be positive. HENCE, the reaction takes place (b) To predict the reaction of silver with sulphuric acid: if it reacts, the following reaction should take place: `2Ag+H_(2)SO_(4)toAg_(2)SO_(4)+H_(2),"i.e.,"2Ag+2H^(+)to2Ag^(+)+H_(2)` By convention, the cell may be represented as : `AG|Ag^(+)||H^(+)|H_(2)` `E_(cell)^(@)=E_(H^(+),H_(2))^(@)-E_(Ag^(+),Ag)^(@)=0-0.80=0.80` volt. |
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