Question

Metallic tin in the presence of $HCl$ is oxidized by $K_{2}C{r}_2{O}_7$ to stannic chloride, $SnC{l}_4$. What volume of deci-normal dichromate solution would be required by $11.9g$ of tin?
(Atomic mass of Sn $=119u$)

• A. $4mL$
• B. $10mL$
• C. $4L$
• D. $10L$

Answer 1

The correct option is C $4L$

$K_2\stackrel{+6}{C}{r}_2{O}_7+\stackrel{0}{S}n\to \stackrel{+3}{C}{r}^{3+}+\stackrel{+4}{S}nC{l}_4$

$n_f=\left(|\text{Change in O.S.}|\right)\times \text{Number of atoms}$
$n_{f_{K_{2}C{r}_2{O}_7}}=|+3-(+6)|\times 2=6$
$n_{f_{Sn}}=|+4-\left(0\right)|\times 1=4$

From the law of equivalence,
$\text{Equivalents of}{K}_{2}C{r}_2{O}_7=\text{Equivalents of}Sn$
$\frac{1}{10}\times V_{K_{2}C{r}_2{O}_7}=\frac{11.9}{119}\times 4$
$\therefore V_{K_{2}C{r}_2{O}_7}=4L$