Answer:
[tex]\large \boxed{\text{12.0 mol/L}}[/tex]
Explanation:
The formula for molar concentration c is
[tex]c = \dfrac{\text{moles}}{\text{litres}}\\\\c = \dfrac{\text{3.00 mol}}{\text{0.250 L}} = \textbf{12.0 mol/L }\\\\\text{The molar concentration of the solution is $\large \boxed{\textbf{12.0 mol/L}}$}[/tex]