Question

Nitric acid + _____________________ ---> potassium nitrate + ________________

Answer 1

The most common way to get potassium nitrate from nitric acid is the reaction with potassium hydroxide

HNO₃ + KOH $\to$ KNO₃ + H₂O

Nitric acid + Potassium hydroxide $\to$ Potassium nitrate + Water

Other options:

2HNO₃ + K₂O → 2KNO₃ + H₂O

2HNO₃ + K₂CO₃$\to$ 2KNO₃ + H₂O + CO₂