Question

Given : $A^{2+}+2e^{-}\to A\left(s\right)$ $E^{\ominus }=0.08V$
$B^{\oplus }+e^{-}\to B\left(s\right)$ $E^{\ominus }=-0.64V$
$X_2\left(g\right)+2e^{-}\to 2X^{\ominus }$
$E^{\ominus }=1.03V$
Which of the following statements is/are correct ?

• A. $X_2\left(g\right)$ will oxidize both (A) and (B ).
• B. $A^{2+}$ will oxidize B.
• C. The reaction $2X^{Pominus}\left(1.0M\right)+A^{2+}\left(1.0M\right)\to X_2\left(1atm\right)+A\left(s\right)$ will be spontaneous.
• D. The oxidizing power of $A^{2+},B^{\oplus }$, and $X_2\left(g\right)$ is in the order $X_2>A^{2+}>B^{\oplus }$

Answer 1

Answer: (A), (B), (D)

$X_2\left(g\right)$ will oxidize both (A) and (B ).
$A^{2+}$ will oxidize B.
The oxidizing power of $A^{2+},B^{\oplus }$, and $X_2\left(g\right)$ is in the order $X_2>A^{2+}>B^{\oplus }$

$E_{cell}^{\ominus }$ corresponding to the reaction is : $2X^{\ominus }\left(1M\right)+A^{2+}\left(1.0M\right)\to X_2\left(1atm\right)l+A\left(s\right)$

$E_{cell}^{\ominus }=E_{A^{2+}|A}^{\ominus }-E_{X_{2}2X^{\ominus }}^{\ominus }=0.081.30=-1.22V$

$E_{cell}^{\ominus }$ is negative, so $\Delta G^{\ominus }$ will be (+ve) and hence reaction (c) will not be feasible.

So, statement (c) is wrong. Statements (a), (b), and (d) are correct.