Question

Assertion : $E^{\circ }$ for $M{n}^{3+}/M{n}^{2+}$ is more positive than $C{r}^{3+}/C{r}^{2+}$
Reason : The third ionization energy of $Mn$ is larger than that of $Cr$.

• A. If both assertion and reason are true and reason is the correct explanation of the assertion
• B. If both assertion and reason are true but reason is not the correct explanation of the assertion
• C. If assertion is true, but reason is false
• D. Both assertion and reason are false statements

Answer 1

Answer: (B)

$Mn$ has more oxidation potential than $Cr$. It is present below that $Cr$ in $ECS$ . So its reduction potential is less than $Cr$. $E_{\text{cell }}^{\circ }$ is more the third ionisation energy for $Mn$ is $3258kJmo{l}^{-1}$ and for $Cr$ is $2994kJmo{l}^{-1}$. So both the statements are true but not correct explanation.