Question

$S{O}_2$ and $C{O}_2$ both turn lime water $\left(A\right)$ milky coloured, $S{O}_2$ also turns $K_{2}C{r}_2{O}_7/H^{+}\left(B\right)$ green while $O_2$ is soluble in pyrogallol $\left(C\right)$ turning it black. These gases are to be detected in order by using these reagents. The correct order is :

• A. $\left(A\right),\left(B\right),\left(C\right)$
• B. $\left(B\right),\left(C\right),\left(A\right)$
• C. $\left(B\right),\left(A\right),\left(C\right)$
• D. $\left(A\right),\left(C\right),\left(B\right)$

Answer 1

Answer: (C)

$\left(B\right),\left(A\right),\left(C\right)$

$S{O}_2$ and $C{O}_2$ both turn lime water $\left(A\right)$ milky, $S{O}_2$ also turns $K_{2}C{r}_2{O}_7/H^{+}\left(B\right)$ green while $O_2$ is soluble in pyrogallol $\left(C\right)$ turning it black. These gases are to be detected in order by using these reagents. The order is $\left(B\right),\left(A\right),\left(C\right)$. $\left(B\right)$ will absorb $S{O}_2$ first. Thus, it will be removed from the mixture. Then $\left(A\right)$ will absorb $C{O}_2$. Thus, it will also be removed from the mixture. Now $\left(C\right)$ will absorb oxygen.