Question

What volume of 0.50 M $CaC{l}_2$ solution is needed to prepare 250 mL of solution that has a chloride concentration of 0.100 M?

• A. 12.5 mL
• B. 25.0 mL
• C. 50.0 mL
• D. 100 mL

Answer 1

Answer: (B)

The chemical reaction is given as follows

${CaCl}_2⟶{Ca}^{2+}+2C{l}^{-}$

$0.5M0.5M2\times 0.5M=1M$

The solution of 1 M

${Cl}^{-}$

is diluted to 250 ml .

Hence by sing the formula

$M_1{V}_1=M_2{V}_2$

$V_1=\frac{M_2{V}_2}{M_1}=$

$=\frac{0.1\times 250}{1}$

$V_1=25ml$