Given, concentration of solution = 1 x 10^{-4} mol/dm^{3}

absorbance = A = 30

length of cuvette = 1cm

as we know

absorbance A = log\(\frac{I_0}{I}\) = εbc

where

b = length of cuvette

c = concentration of solution

ε = molar absorptivity

A = absorbance

∴ 30 = ε x 1 cm x 1.0 x 10^{-4} mol/dm^{3}

ε = \(\frac{30}{1\ cm\times\ 1.0\times\ 10^{-4}mol/dm^3}\)

ε = 30 x 10^{4 }L mol^{-1}cm^{-1}

or ε = 3.0 x 10^{5} Lmol^{-1}cm^{-1}

Hence, the molar absorptivity (ε) will be 3.0 x 10^{5} Lmol^{-1}cm^{-1}

While the reduction potential of fe (iron) is less than H^{+} but greater than H_{2}0 because at that iron does not corrode in alkaline.