Question

What volume of water would be needed to dilute $50mL$ of a $3M$ $HCl$ solution to $1M$?

• A. $25mL$
• B. $50mL$
• C. $75mL$
• D. $100mL$
• E. $150mL$

Answer 1

Answer: (D)

$100mL$

When performing a dilution you can use the relationship:

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

Where:

$M_1=$ Molarity of the original solution

$V_1=$ Volume of the original solution

$M_2=$ Molarity of the final solution

$V_2=$ Volume of the final solution

Substituting:

$50\times 3=1\times V_2$

$V_2=150ml.$

This is the final Volume.

Therefore, you need 100 ml of water to make a final volume of 150 because 50 ml comes from the Original Volume of 3M HCl.