what type of reaction is ammonium nitrate?

HNO3(aq) + NH3(l) --> NH4NO3(aq)

This is a synthesis, or combination reaction.

a synthesis reaction?

i thought it was an acid-base reaction

it doesn't make sense if it's a synthesis reaction

Oh but it does.

You're right, it is an acid reacting with a base to give a salt; however, the type is synthesis.
Do you know the types?
synthesis
decomposition
single replacement
double replacement
Here is a link.
https://www.google.com/search?q=types+of+reaction&ie=utf-8&oe=utf-8

The reaction you have mentioned is a neutralization reaction. In this reaction, an acid (nitric acid, HNO3) reacts with a base (ammonia, NH3) to form a salt, which is ammonium nitrate (NH4NO3), and water (H2O) as a byproduct.

To determine the type of reaction, you can recognize the reaction pattern. In this case, the reaction involves the combination of an acid and a base to form a salt and water. This pattern is known as a neutralization reaction.

Neutralization reactions occur when an acid and a base come into contact, resulting in the formation of a salt and water. Acids are substances that donate protons (H+ ions), while bases are substances that accept protons. In this reaction, the nitric acid donates a proton to the ammonia, resulting in the formation of the ammonium ion (NH4+).

To summarize, the reaction of nitric acid and ammonia to form ammonium nitrate is a neutralization reaction, where an acid and a base react to form a salt and water.