Question

Assertion:It is safe to stir 1M \[AgN{{O}_{3}}\] solution with a copper spoon.
Reason: \[\begin{align}
  & E_{A{{g}^{+}}/Ag}^{-}=0.80V \\
 & E_{C{{u}^{2+}}/Cu}^{-}=0.34V \\
\end{align}\]
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

Hint: The element with high electrode potential value undergoes reduction and electrode with low electrode potential undergoes oxidation. These two electrodes combine and form a complete cell. If the emf of the cell is positive then the cell exists.

Complete answer:
We cannot stir a silver nitrate solution with a copper spoon because Copper is more reactive (less electrode potential) than silver (high electrode potential). Copper will displace silver from silver nitrate and forms blue color copper nitrate solution.
 Therefore the Assertion is false.
Coming to reason.
\[\begin{align}
  & E_{A{{g}^{+}}/Ag}^{-}=0.80V \\
 & E_{C{{u}^{2+}}/Cu}^{-}=0.34V \\
\end{align}\]
The cell representation for the silver and copper is as follows according to the given values.

\[\begin{align}
  & E_{cell}^{-}=E_{A{{g}^{+}}/Ag}^{-}-E_{C{{u}^{2+}}/Cu}^{-} \\
 & \text{ }=\text{ }0.80-0.34 \\
 & \text{ = 0}\text{.46} \\
\end{align}\]
\[E_{cell}^{-}\] is positive so the cell exists. So, Reason is true.
Therefore it is not safe to stir the silver nitrate solution with a copper spoon.
\[Cu+AgN{{O}_{3}}\to CuN{{O}_{3}}+Ag\]
In the question the Assertion is false and reason is true.

So, the correct option is D.

Note:
As time goes on a white precipitate of Silver metal (Ag) will be formed and the Solution changes it color gradually to blue in color owing to the formation of Copper Nitrate (\[CuN{{O}_{3}}\]). Copper acts as anode and silver acts as cathode. Copper loses its electrons and silver gains electrons.