What is the heat of formation of $$\mathrm{HCl}_{(\mathrm{g})}$$ from following equation?

$$\mathrm{H}_{2(\mathrm{~g})}+\mathrm{Cl}_{2(\mathrm{g})} \rightarrow 2 \mathrm{HCl}_{(\mathrm{g})} \Delta_{\mathrm{f}} \mathrm{H}=-194 \mathrm{~kJ}$$

Identify the concentration of the solution from following so that values of ,$$\Delta \mathrm{T}_{\mathrm{f}}$$ and $$\mathrm{K}_{\mathrm{f}}$$ are same.

What is the product formed when cumene is air oxidised in presence of Co-naphthenate and further treated with dilute acid?

Identify the use of polystyrene for household purposes.