For example formation of a precipitate as in the following reaction:
NaCl + AgNO3 = AgCl(s) + NaNO3
Silver chloride is a white precipitate.
This depends on each chemical reaction involved.
A reaction doesn't occur.
The chemical reaction is:AgNO3 + NaCl = AgCl + NaNO3Silver chloride is a white precipitate.
HCl + NaOH ==> NaCl + H2O
A Double displacement reaction or Neutralization reaction
Any chemical reaction is possible.
Double Replacement
I think the answer you're looking for is a "Chemical Reaction". For instance, combining Hydrochloric Acid (HCl) and Sodium Hydroxide (NaOH) will cause a Chemical Reaction resulting in salt water (NaCl + H20).
Nacl
The reaction is:NaOH + HCl = NaCl + H2O
The reaction is:NaOH + HCl = NaCl + H2O
Signs of physical change - Change in appearance,taste,display of substance Signs of chemical change- Change in chemical reaction