Question

How many grams of NaCl will be required to make a $100$. milliliters of $2$M solution?

• A. $5.85$
• B. $11.7$
• C. $29.2$
• D. $58.5$
• E. $117$

Answer 1

The correct option is B $11.7$

100 mL of 2 M solution will contain
$\frac{100mL}{1000mL/L}\times 2mol/L=0.2$ moles of $NaCl$
The atomic masses of $Na$ and $C{l}_2$ are 23 g/mol and 35.5 g/mol respectively.
The molar mass of $NaCl=23+35.5=58.5$ g/mol
0.2 moles of $NaCl$ corresponds to
$0.2\times 58.5=11.7$ grams