Question

When the sodium fusion extract of an organic compound is treated with lead acetate solution, the formation of a black-precipitate confirms the presence of the element:

• A. nitrogen in the compound
• B. sulphur in the compound
• C. chlorine in compound
• D. bromine in the compound
• E. phosphorus in the compound

Answer 1

Answer: (B)

When a sodium fusion extract of an organic compound is treated with lead acetate solution, a black precipitate of $PbS$ is formed. It confirms the presence of the element S. The reaction takes place as:
$N{a}_{2}S+{(C{H}_{3}COO)}_{2}Pb\to \underset{\begin{array}{c}leadsulphide\\ (blackppt.)\end{array}}{\mathrm{PbS}}$ $+2C{H}_{3}COONa$