Question

How many mL of pure isopropyl alcohol is needed to prepare 250 mL of 70% isopropyl alcohol (C3H7OH). I'm thinking if i should use vol of solute/vol of sol'n but it doesn't fit the formula and im confuse it. please help me

Answer 1

This is just a dilution.
mL x % = mL x %
250mL x 70% = ?mL x 100%