Question

25.0g of NaCl is placed in a 100.0ml volumetric flask. Enough water is added to dissolve the salt and then the volume is brought to 100.0ml total. What is the molar (moles/L or M) concentration of the NaCl?

Answer 1

Answer : The molar concentration of
`NaCl` in the solution is, 4.27 M

Explanation : Given,

Mass of
`NaCl` = 25.0 g

Volume of solution = 100.0 mL

Molar mass of
`NaCl` = 58.5 g/mole

Molarity : It is defined as the number of moles of solute present in one liter of volume of solution.

Formula used :

`\text{Molarity}=\frac{\text{Mass of }NaCl* 1000}{\text{Molar mass of }NaCl* \text{Volume of solution (in mL)}}`

Now put all the given values in this formula, we get:

`\text{Molarity}=(25.0g* 1000)/(58.5g/mole* 100.0mL)=4.27mole/L=4.27M`

Therefore, the molar concentration of
`NaCl` in the solution is, 4.27 M