Question

11. A powdered salt (X) in a dry test tube
was heated that evolves brown fumes of
nitrogen dioxide and a yellow residue of
lead oxide is also formed. The salt is​

Answer 1

Given:

A powdered salt (X) in a dry test tube was heated that evolves brown fumes of nitrogen dioxide and a yellow residue of lead oxide is also formed.

To find:

The name of salt X.

Solution:

The unknown reaction happened in the following manner :

$\boxed{\sf{X \overset{\Delta}{\longrightarrow} NO_{2}+PbO+O_{2}}}$

Now , this reaction is possible only when the salt is Lead (II) Nitrate. Now , let's see the actual reaction:

$\boxed{\sf{Pb(NO_{3})_{2} \overset{\Delta}{\longrightarrow} NO_{2}+PbO+O_{2}}}$

Now , the balanced Equation:

$\boxed{\sf{2Pb(NO_{3})_{2} \overset{\Delta}{\longrightarrow} 4NO_{2}+2PbO+O_{2}}}$

• Actually this test is a preliminary test for NO3- radicle.

• After heating the salt in dry test tube , we get to see the reddish-brown fumes of NO2.