Question

A solution of H2SO4(aq) with a molal concentration of 3.97 m has a density of 1.216 g/mL. What is the molar concentration of this solution?

Answer 1

molaL concentration is defined as:\[m = \frac{mol \space solute}{kg \space solvent};\]where molaR concentration is:\[M = \frac{mol \space solute}{L \space solution}.\]
You need to change the denominator of that ratio from kg to L, using the density of the solution provided. A density of 1.216g/mL is equal to 1.216kg/L (multiplying both top and bottom by a factor of 1000). This is mainly a unit conversion exercise, you don't really have to know much about solutions to change the units on the bottom.