Final answer:
2) NH₃ NaOH is the compound expected to be a strong base in water out of the options provided.
Step-by-step explanation:
The compound expected to be a strong base in water is NaOH. Among the compounds listed, HCl, H₂SO₄, and HNO₃ are strong acids, and NH₃ (ammonia) is only a weak base. Strong bases are typically hydroxides of alkali metals and some alkaline earth metals, such as NaOH.
The ability of NaOH to dissociate completely in water makes it a strong electrolyte and a strong base. In contrast, compounds like NH₃, while they do have basic properties, do not fully dissociate in water and therefore are classified as weak bases.