Question

$x$ moles of potassium dichromate oxidises $1$ mole of ferrous oxalate, in acidic medium. Here $x$ is

• A. 3
• B. 1.5
• C. 0.5
• D. 1.0

Answer 1

Answer: (C)

The reaction of oxidation of ferrous oxalate by potassium dichromate in acidic medium is written as
$2 FeC _{2} O _{4}+ Cr _{2} O _{7}^{2-}+14 H ^{+} \longrightarrow 2 Fe ^{3+}+2 Cr ^{3+}+4 CO _{2}+7 H _{2} O$
$\because 2$ moles of $FeC _{2} O _{4}$ are oxidised by $=1$ mole of $Cr _{2} O _{7}^{2-}$
$\therefore 1$ mole of $FeC _{2} O _{4}$ will be oxidised by $=\frac{1}{2}=0.5$ mole of $Cr _{2} O _{7}^{2-}$