Question

Which species in each of the following pairs is better reducing agent under standard state conditions? Give reasons for your answer.

• A. $K\left(s\right)(-2.93V)$ or $Mg\left(s\right)(-2.36V)$
• B. $C{o}^{2+}\left(aq\right)\left(1.81V\right)$ or $In\left(s\right)(-0.14V)$
• C. $C{e}^{3+}\left(aq\right)\left(1.61V\right)$ or $T{i}^{2+}(-0.37V)$
• D. $Hg\left(l\right)\left(0.86V\right)$ or $Ni\left(s\right)(-0.23V)$

Answer 1

The correct option is A $K\left(s\right)(-2.93V)$ or $Mg\left(s\right)(-2.36V)$

$\to$ $K_{\left(s\right)}(-2.93V)$ or ${Mg}_{\left(s\right)}(-2.36V)$

$\to$ The magnitude of $E^0$ is a measure of the tendency of the half cell reaction to occur in the forward direction.

$\to$ The higher its positive value, the greater is the tendency of the oxidized form to get reduced by accepting electrons.

$\to$ And, conversely, the greater the negative value, the greater is the tendency of the reduced form to get oxidized by donating electrons.

$\to$ Greater negative value of $K$ & $Mg$ shows their better reducing power.