Q51 / 180 · COMEDK 2026 (9 May Shift 2) · Chemistry

Using the data given below, the strongest reducing agent is:
$E^o_{\text{Cr}_2\text{O}_7^{2-}/\text{Cr}^{3+}} = 1.33$ V    $E^o_{\text{MnO}_4^-/\text{Mn}^{2+}} = 1.51$ V
$E^o_{\text{Cl}_2/\text{Cl}^-} = 1.36$ V    $E^o_{\text{Cr}^{3+}/\text{Cr}} = -0.74$ V

  • Correct answer
    A
    $Cr$
  • B
    $Cl^-$
  • C
    $Mn^{2+}$
  • D
    $Cr^{3+}$

Solution

A reducing agent undergoes oxidation. The strength of a reducing agent is directly proportional to its standard oxidation potential, which is the negative of its standard reduction potential.

The standard oxidation potentials for the given species are:
$E^o_{\text{Cr}/\text{Cr}^{3+}} = -(-0.74) = +0.74$ V
$E^o_{\text{Cl}^-/\text{Cl}_2} = -1.36$ V
$E^o_{\text{Mn}^{2+}/\text{MnO}_4^-} = -1.51$ V
$E^o_{\text{Cr}^{3+}/\text{Cr}_2\text{O}_7^{2-}} = -1.33$ V

Since $Cr$ has the highest standard oxidation potential ($+0.74$ V), it has the greatest tendency to get oxidized. Therefore, $Cr$ is the strongest reducing agent among the given options.

Answer: $Cr$

Hence, the correct answer is option: 'A'.

Relevant Questions