If 1.0 mol L−1 NaX(aq) contains 7.4% solute by mass, what is the molar mass of X? Choose the closest answer. Assume the density of this solution is approximately equal to that of water, 1.0 g/mL.
A 17 g mol−1 *B 51 g mol−1 C 74 g mol−1
D 98 g mol−1
E 120 g mol