Answer: The standard state refers to 1 atm and [tex]25^{o}C[/tex].
Explanation:
It is known that a chemical/substance can either be present in a solid, liquid or gaseous state.
So, when the phase of a substance like solid, liquid or gas is present at 1 atmosphere pressure and at a temperature of [tex]25^{o}C[/tex] then it known as standard state of substance.
Thus, we can conclude that standard state refers to 1 atm and [tex]25^{o}C[/tex].
