CBSE Class 10 Science 2019 · Paper 31/3/1 · Question 16(b)

(a) Take about $2$ g of lead nitrate powder in a boiling tube, hold the tube with a pair of tongs and heat it over a burner flame, with its mouth pointed away from everyone; lead nitrate decomposes. (b) Labelled diagram: boiling tube containing lead nitrate powder, held with a pair of tongs over a burner flame, with brown fumes of nitrogen dioxide leaving its mouth. Observations: (1) brown fumes of nitrogen dioxide are given off; (2) a residue of lead(II) oxide is left, reddish brown while hot and yellow when cold. (c) $2{\text{Pb(NO}}_3{)}_2\text{(s)}\stackrel{\text{heat}}{\to }2\text{PbO(s)}+4{\text{NO}}_2\text{(g)}+{\text{O}}_2\text{(g)}$: lead nitrate (solid) gives lead(II) oxide (solid), nitrogen dioxide (gas) and oxygen (gas).