Question

The label of the 500-mL rubbing alcohol that Mike bought shows that it contains 70% ethyl alcohol. How many mL of ethyl alcohol is present in the solution?
A. 100 mL
B. 200 mL
C. 375 mL
D. 500 mL

Answer 1

Answer:

Hence, 500 ml will contain - 350 ml ethyl alcohol. Amount of water - 150 ml. Therefore, 70% volume by volume solution of ethyl alcohol of 500 ml will be made by addition of 350 ml ethyl alcohol and 150 ml water.

Answer 2

Given:

The strength of isopropyl alcohol = $70\%$

The volume of rubbing alcohol = $500$ ml

To find:

The volume of isopropyl alcohol is used to make $500$ mL of rubbing alcohol

Formula:

$Percent\;by\;volume\;=\;\frac{Volume\;of\;solute}{Volume\;of\;solution}\;\times\;100$

Explanation:

The volume of isopropyl alcohol present in  $500$ mL of rubbing alcohol

⇒ $\frac{70}{100}\;\times\;500$

The volume of isopropyl alcohol = $350$ ml

Answer:

The volume of isopropyl alcohol present in  $500$ mL of rubbing alcohol is  $350$ ml