Net ionic equation for acid-base neutralization

Steps:

• Balance molecular equation: Ca(OH)₂(aq) + 2HNO₃(aq) → Ca(NO₃)₂(aq) + 2H₂O(l)
• Dissociate into ions: Ca²⁺ + 2OH⁻ + 2H⁺ + 2NO₃⁻ → Ca²⁺ + 2NO₃⁻ + 2H₂O
• Cancel spectator ions Ca²⁺ and 2NO₃⁻ from both sides
• Result: net ionic OH⁻ + H⁺ → H₂O, with salt from remaining ions Ca²⁺ + 2NO₃⁻

Why D is correct:

• Represents ionic equation by showing H⁺/OH⁻ combination to water and Ca²⁺/NO₃⁻ to salt, per definition of ionic equations focusing on reacting species.

Why the others are wrong:

• A: Includes undissociated species and wrong salt formula CaNO₃ (should be Ca(NO₃)₂)
• B: Full molecular equation, ignores dissociation into ions
• C: Lacks clear separation of neutralization and salt formation, misrepresenting net ionic form

Final answer: D