Question

Which of the following are acceptable ways to make one liter of 1 M NaCl?
a) Put 1 liter of water into a container, then add 1 mole of NaCl and stir until the NaCl dissolves.
b) Put 1 mole of NaCl into a container, then add 1 liter of water and stir until the NaCl dissolves.
c) Put 1 mole of NaCl into a container, then add water with stirring until the total volume reaches 1 liter

Need by 9/3/18, 11:59pm

Answer 1

Initially, weigh the correct amount of $NaCl$ calculated from the formula.

Number of moles  =$\frac{Given mass in g}{Molar mass}$

As 1 mole of $NaCl$ is given and molar mass of $NaCl$ is $58.44 g/mol$, then

1 mole of $NaCl$= $\frac{Given mass in g}{58.44 g/mol}$

Mass of $NaCl$ in g = ${58.44 g}$

Thus,

1 mole of $NaCl$ = 58.44 g.

Now, the weighed amount of $NaCl$ i.e. 58.44 g is added to a 1 liter container and then add small amount of water in the container to dissolve the salt. After that, fill the container with distilled water to the graduation mark or until the total volume reaches 1 liter.

Thus, option (c) is correct i.e. first put one mole of salt in the container then add the water with stirring till the total volume reaches 1 liter.