[tex]\large\text{Dados:}\\\\\begin{cases}M=~?\\m=900g\\v=2l\\Mm~\Rightarrow~(Nal)=150g/mol\end{cases}\\\\\boxed{\boxed{M=\frac{m}{Mm~\cdot~v}}}\bigstar\\\\M=\frac{900\diagup\!\!\!\!\!g}{150\diagup\!\!\!\!\!g/mol~\cdot~2l}\\\\M=6~mol\cdot2l\\\\\boxed{\blue{M=12~mol/l}}\checkmark[/tex]
