Question

Assertion: It is safe to stir 1 M $AgN{O}_3$ solution with a copper spoon.
Reason: $E_{A{g}^{\oplus }|Ag}^{\ominus }=0.80V$.
$E_{C{u}^{2+}|Cu}^{\ominus }=0.34V$.

• A. Both Assertion and Reason are true and Reason is the correct explanation of Assertion
• B. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
  
• C. Assertion is true but Reason is false
• D. Assertion is false but Reason is true
  
• E. Both Assertion and Reason are false

Answer 1

The correct option is D Assertion is false but Reason is true

$E_{Ag|Ag}^{\ominus }>E_{C{u}^{2+}|Cu}^{\ominus }$
Cell representation : $Cu|Cu||A{g}^{\oplus }|Ag$
So for spontaneity of reaction, $A{g}^{\oplus }|Ag$ will undergo reduction and $Cu|C{u}^{2+}$ will undergo oxidation.
If $E_{cell}^{\oplus }$ is positive, reaction will take place, i.e., on stirring a solution of $AgN{O}_3$ with Cu spoon will not be possible. Since Cu spoon will dissolve in $AgN{O}_3$ solution.
$\therefore E_{cell}^{\ominus }=(E_{A{g}^{\oplus }|Ag}^{\ominus }{)}_c-(E_{C{u}^{2+}|Cu}^{\ominus }{)}_a$ = (0.80 - 0.34) = 0.46.
$E_{cell}^{\ominus }$ is (+ve). So it is not safe to stir $AgN{O}_3$ with Cu spoon.