What is the % v/v of ethanol in a solution if 10 ml of ethanol is added to 90 ml of water ?

Answer 1

% v/v means mls of solute per 100 mls of solution. In this example, ethanol is the solute, so you have 10 ml ethanol in a total of 100 ml of solution (assuming the volumes are additive, which they are not).

10 ml/100 ml (x100%) = 10 % v/v