Question

What will be observed if gas $X$ is bubbled into limewater?

• A. It turns milky
• B. It decolurises
• C. It turns violet
• D. It turns red

Answer 1

Answer: (A)

It turns milky

Since $X$ is a colourless gas and on passing $X$ on overheated $4C$ another colourless gas is obtained. So, $4X$ must be $C{O}_2$.

$C{O}_2+C$ $⟶$ $2CO$

So, $Y$ is $CO$. $CO$ burns in $O_2$ to form $C{O}_2$

$2CO+O_2$ $⟶$ $C_2$

Now, if $C{O}_2$ is bubbled in lime water, it turns milky due to formation of insoluble calcium carbonate.

$Ca(OH{)}_2+C{O}_2$ $⟶$ $2C{O}_2$ .