Question

A student while heating solid lead nitrate taken in a test tube would observe (1) white residue of PbO2
(2) green residue of NO2
(3) yellow residue of PbO
(4) brown residue of NO

Answer 1

Answer:

Yellow residue of PbO.

Explanation:

This is because Lead nitrate is a colourless liquid. On heating it, it releases Nitrogen Dioxide and Oxygen gas. The left over solid is Lead Oxide which is yellow in colour. On heating Lead Nitrate you will first see the test tube appearing brown due to the Brown Fumes of NO2 but after some time, you will be able to see the yellow Lead Oxide.

Answer 2

A student while heating solid lead nitrate taken in a test tube would observe (3) yellow residue of PbO (lead oxide)

Explanation:

When the lead nitrate ( $PbNO_3$ ) is burned, the yellow residue of lead dioxide (PbO) is received and a brown gas, nitrogen dioxide ($NO_2$), is released along with the emission of oxygen $O_2$ gas .

The corresponding chemical reaction is as follows below

$2Pb(NO_3)_2 (heated) -> 2PbO+ 4NO_2+ O_2$

So option 3)yellow residue of PbO is the right answer.