Question

Question: Which of the following must be known to calculate the molarity of a salt solution (there may be more than one answer)?

1. The mass of salt added
2. The molar mass of the salt
3. The volume of water added
4. The total volume of the solution explain

Short answer

1. The molar mass of the salt
2. The molar mass of the salt
3. The volume of water added
4. The total volume of the solution

Step-by-step solution

The mass of salt added

$\text{Molarity} \text{=} \frac{\text{Moles} \text{of} \text{solute}}{\text{Liters} \text{of} \text{solution}}$

$\text{Molarity}$

Molarity can be defined as moles of solute in per volume of solution. Here the mass of salt added in grams to the solution. Therefore, it gives only the how much of chemical in the solution.

The molar mass of the salt

$\mathrm{Number}\mathrm{of}\mathrm{moles}\mathrm{of}\mathrm{salt}\mathrm{present}\mathrm{in}\mathrm{solution}=\frac{\mathrm{Mass}\mathrm{of}\mathrm{the}\mathrm{solute}\left(\mathrm{salt}\right)\mathrm{added}}{\mathrm{Molar}\mathrm{mass}\mathrm{of}\mathrm{the}\mathrm{solute}\left(\mathrm{salt}\right)}$

So, the molar mass of the salt aids to calculate the molarity of the salt solution.

The volume of water added

If we adding the water to dilute the salt solution, there will exist less no of moles in salt solution. Hence, known the volume of water in important to calculate molarity of the solution.

The total volume of the solution explain

To calculate the molarity of the solution must to known the volume of the solution.

Conclusion

Hence, the mass of salt, volume of water added, total volume of solution, and molar mass of salt is needed to calculate the molarity if the salt solution.