If the density of some lake water

Hint:We can calculate the molarity of sodium ions in the lake using the moles of solute to the mass of the solvent (in kilograms). The moles of solute are nothing but the moles of sodium ions. The moles of sodium ions are calculated using the mass of sodium ions divided by the molar mass of sodium ions. Complete step by step answer: Given data contains, Density of some lake water is $1.25gm$ Molality of sodium ions=$4m$ The molality of the sodium ions in the lake is $4m$. Note: We have to know the major benefit of using molality as a unit of concentration is that molality is dependent on the amounts of solute and solvent that is not affected by changes in temperature and pressure. In many applications, the molality carries a major advantage because the mass or the amount of a substance is frequently more essential than its volume. Another major advantage of molality is that the molality of one solute present in a solution is independent of the absence (or) presence of other solutes.