Question

For which of the following reactions is Gay-Lussac’s law not valid?

• A. $PC{l}_5\text{(g)}\to PC{l}_3\text{(g)}+C{l}_2\text{(g)}$
• B. $H_2\text{(g)}+C{l}_2\text{(g)}\to 2HCl\text{(g)}$
• C. $2S{O}_2\text{(g)}+O_2\text{(g)}\to 2S{O}_3\text{(g)}$
• D. $2KCl{O}_3\text{(s)}\to 2KCl\text{(s)}+3O_2\text{(g)}$

Answer 1

The correct option is D $2KCl{O}_3\text{(s)}\to 2KCl\text{(s)}+3O_2\text{(g)}$

Gay-Lussac’s law is only valid for gases. Therefore, reactants and products both must be gases.