Question

Assertion :In ammonia solution, mercurous chloride gives a black precipitate consisting of a mixture of chloro-mercuric amide and elemental mercury. Reason: Mercurous chloride is unstable in room temperature.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is B Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

When $ammonia$ solution reacts with $mercury\left(I\right)$ $chloride$ and it forms white precipitate of $mercury\left(II\right)$ $amido$ $chloride$ and $merkury$ $metal$. Both of these are insoluble precipitate.

$Mercury\left(II\right)$ $amido$ $chloride$ is a white precipitate but mercury metal in finely divided state makes it shiny black.

$H{g}_{2}C{l}_2+2N{H}_3⟶Hg\downarrow +Hg\left(N{H}_2\right)Cl\downarrow +N{H}_4^{+}+C{l}^{-}$

$Mercurous$ $chloride$ is unstable at room temperature$\left(H{g}_{2}C{l}_2\right).$