Question

What volume of $0.05M{K}_{2}C{r}_2{O}_7$ in acidic medium is needed for complete oxidation of $200$ mL of $0.6M$ $Fe{C}_2{O}_4$ solution?

• A. $1.4$ L
• B. $1.2$ L
• C. $120$ mL
• D. $800$ mL

Answer 1

Answer: (B)

$1.2$ L

$\underset{0.05M}{C{r}_2{O}_7^{2-}}+\underset{0.6M/200mL}{Fe{C}_2{O}_4}\stackrel{H^{⨁}}{\to }$ $C{r}_2{O}_7^{2-}+14H^{⨁}+6e^{-}\to 2C{r}^{3+}+7H_{2}O$

$F{e}^{2+}\to F{e}^{3+}+e^{-}$;

$C_2{O}_4^{2-}\to 2C{O}_2+2e^{-}$

$Fe{C}_2{O}_4\to F{e}^{3+}+2C{O}_2+3e^{-}$

$m.Eq.of{K}_{2}C{r}_2{O}_7\equiv m.Eq.ofFe{C}_2{O}_4$

$(0.05\times 6)\times V=(0.6\times 3)\times 200$

$\Rightarrow V=1200mL=1.2L$