When an acid and a base react, a particular type of salt is formed. this is an example of what type of reaction? a) physical only b)chemical only c) physical and chemical

B)chemical only

Explanation:

Now, it is important to understand that the reaction described in question is a neutralization reaction which is type of double displacement reaction. It is definitely a chemical reaction.

Now there is a difference between physical and chemical reaction. A physical reaction is one in which matter undergoes a physical change for example melting. In melting, a substance change its form but no change in the structure and composition of molecules occur.

On the other hand, in chemical reaction, change occur on molecular level. Old molecules convert into new molecular compositions. If you take example of Sodium Hydroxide and Hydrochloric acid here

NaOH + HCl → NaCl + H2O

Now you can see that both NaOH and HCl molecules decomposed into new molecules of H2O and NaCl.

Please notice that in physical reaction, no new substance is formed, but only physical appearance changes, that is why, we have to exclude third option "both physical and chemical".

answer

i think the answer is a) as air pressure in an area increases, the density of the gas particles in that area decreases.

hope it