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

When lead nitrate is heated, a yellow residue of lead oxide is obtained, and brown colored gas is liberated, i.e. nitrogen dioxide.
$2\mathrm{Pb}({\mathrm{NO}}_3{)}_2\to 2\mathrm{PbO}+4{\mathrm{NO}}_2+{\mathrm{O}}_2$

Hence, the correct answer is option 3.