Distinguishing weak vs. strong acid dissociation

Steps:

• Recall methanoic acid (HCOOH) is weak, so partial dissociation uses ⇌.
• Recall nitric acid (HNO3) is strong, so complete dissociation uses →.
• Examine options: weak acid must use ⇌; strong acid must use →.
• Select option matching both conventions.

Why D is correct:

• It uses ⇌ for weak HCOOH (equilibrium per weak acid definition) and → for strong HNO3 (complete ionization per strong acid definition).

Why the others are wrong:

• A: Incorrectly formats HNO3 with → but mismatches weak acid arrow in context.
• B: Uses ⇌ for strong HNO3, implying partial dissociation against strong acid law.
• C: Duplicates A's error in arrow placement for acids.

Final answer: D