Question 475050
I'm making a cleaning solution requiring  2% alcohol, my isopropyl alcohol is 70%
how much water do I add to the 70% solution to create 2%, please. 
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It depends on how much you have, or how much you want.
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If you have v liters (or gallons, any units) of 70%, then there's 0.7v of alcohol in it.
For 0.7v to be 2%, then 
total volume = 0.7v/0.02 = 35v units
You add 34v units of water, 34 times whatever your original volume is.
You use 34 units of water for each unit of 70% solution.