Answer:
<span>Ni<span>(s)</span><span><span>∣∣</span>N<span>i<span>2+</span></span><span>(aq)</span> <span>∣∣</span></span><span><span>∣∣</span> A<span><span>g+</span><span>(aq)</span></span><span>∣∣</span></span>A<span>g<span>(s)</span></span></span>
Explanation:
Start by finding the standard reduction potential for the <span>A<span>g+</span></span> and <span>N<span>i<span>2+</span></span></span> ion. Normally, the values are listed at the back of most chemistry textbooks.
<span>A<span><span>g+</span><span>(aq)</span></span>+1<span>e−</span>→A<span>g<span>(s)</span></span> <span>Eo</span>=0.80 V</span>
<span>N<span>i<span>2+</span></span><span>(aq)</span>+2<span>e−</span>→Ni<span>(s)</span> <span>Eo</span>=−0.23 V</span>
In the galvanic cell, the reaction is spontaneous and for a spontaneous reaction <span>E<span>o<span>cell</span></span></span>must be a positive quantity.
<span><span>E<span>o<span>cell</span></span></span>=<span>E<span>o<span>Anode</span></span></span>+<span>E<span>o<span>cathode</span></span></span></span>
Manipulate the two equations so that <span>E<span>o<span>cell</span></span></span> is positive. Note that the anode is the site of oxidation (where electrons are lost) and the cathode (where electron are gained) is the site for reduction.
<span>A<span><span>g+</span><span>(aq)</span></span>+<span>1<span>e−</span></span>→A<span>g<span>(s)</span></span> <span>Eo</span>=0.80 V</span>
<span>Ni<span>(s)</span>→N<span>i<span>2+</span></span><span>(aq)</span>+<span>2<span>e−</span></span> <span>Eo</span>=0.23 V</span>
<span>2×<span>{A<span><span>g+</span><span>(aq)</span></span>+1<span>e−</span>→A<span>g<span>(s)</span></span>}</span> <span>Eo</span>=0.80 V <span>(Cathode)</span></span>
<span>Ni<span>(s)</span>→N<span>i<span>2+</span></span><span>(aq)</span>+2<span>e−</span> <span>Eo</span>=0.23 V <span>(Anode)</span></span>
<span> <span>−−−</span></span>
<span>2A<span><span>g+</span><span>(aq)</span></span>+Ni<span>(s)</span>→N<span>i<span>2+</span></span><span>(aq)</span>+2A<span>g<span>(s)</span></span> <span>E<span>o<span>cell</span></span></span>=1.03 V</span>
Start with the anode components (site of oxidation) - the cathode components are listed to the right.
<span>Ni<span>(s)</span><span><span>∣∣</span>N<span>i<span>2+</span></span><span>(aq)</span> <span>∣∣</span></span><span><span>∣∣</span> A<span><span>g+</span><span>(aq)</span></span><span>∣∣</span></span>A<span>g<span>(s)</span></span></span>
The single vertical lines indicate the boundary (phase difference) between solid <span>Ni</span>and <span>N<span>i<span>2+</span></span></span> ions in the aqueous solution of the first compartment and between solid <span>Ag</span> and <span>A<span>g+</span></span> ions present in the aqueous solution of the second compartments.
The double vertical lines refer to the salt bridge - note that the salt bridge must be an inert salt to both ions present in both compartments of the galvanic cell ...
