Question

25 ml solution has $[C_2{O}_4{]}^{2-}$ ions. It is found to require 10 ml of $\frac{N}{10}$ acidic $K_{2}C{r}_2{O}_7$ for a complete reaction. Find out the molarity of $[C_2{O}_4{]}^{2-}$ in the solution.

• A. $\frac{1}{25}$
• B. $\frac{1}{10}$
• C. $\frac{1}{20}$
• D. $\frac{1}{50}$

Answer 1

The correct option is D $\frac{1}{50}$

$[C_2{O}_4{]}^{2-}+K_{2}C{r}_2{O}_7⟶C{r}^{3+}+C{O}_2$

Meq. of $[C_2{O}_4{]}^{2-}$ = Meq. of $K_{2}C{r}_2{O}_7$
$M\times 2\times 25=10\times \frac{1}{10}$
$\Rightarrow M=\frac{1}{50}$