# Which one of the following reactions does not form gaseous product?

$\begin{array}{1 1}(a)\;PbO_2+H_2O_2\rightarrow\\(b)\;PbS+H_2O_2\rightarrow\\(c)\;Cl_2+H_2O_2\rightarrow\\(d)\;Na_2CO_3+H_2O_2\rightarrow\end{array}$

$PbS+4H_2O_2\rightarrow PbSO_4(solid)+4H_2O(liquid)$
Hence (b) is the correct answer.