Consider the given data: (a) \(\mathrm{HCl}(\mathrm{g})+10{\mathrm{H}}_{2}\mathrm{O}(\mathrm{l})\to \mathrm{HCl}.10{\mat…

ΔH < 0 ⇒ dissolution of HCl(g) is exothermic.

HCl(g) + 10H₂O(l) → HCl·10\({\mathrm{H}}_{2}\mathrm{O}\)
ΔH₁ = −69.01 kJ mol⁻¹

HCl(g) + 40\({\mathrm{H}}_{2}\mathrm{O}\)(l) → HCl·40\({\mathrm{H}}_{2}\mathrm{O}\)
ΔH₂ = −72.79 kJ mol⁻¹

Heat of dilution
= ΔH₂ − ΔH₁
= −72.79 − (−69.01)
= −3.78 kJ mol⁻¹

⇒ Heat of solution depends on amount of solvent.
⇒ Option (3) is incorrect.

For heat of formation, reactants must be in elemental state ⇒ Option (4) is incorrect.