Question

What is $70$ ( $\dfrac{v}{v}$ ) ethyl alcohol? And what constitutes the other $30$ ?

Answer 1

A solution is made when some amount of solute is mixed in a certain amount of solvent. There are many concentration terms in which we can define the concentration of the solution. V/V is the concentration term which describes the volume percent of solute which is present in a certain volume percent of the solvent (We do not take solution term here).

Complete Step By Step Answer:
We know that a solution consists of a solute and a solvent. There are many concentration terms in which we can define the concentration of the solution and one such concentration term is volume/volume which can be written as $\dfrac{v}{v}$ .
Where, v in the numerator is the volume of the solute and v in the denominator is the volume of the solvent.
In simple terms, we can define $\dfrac{v}{v}$ as the percentage of ratio of volume of solute and volume of solvent.
So, we are given $70$ ( $\dfrac{v}{v}$ ) ethyl alcohol, which means that if the total volume of the solution is $100ml$ , then $70ml$ of ethyl alcohol will be present in that solution. Therefore, the volume percent of the solvent will be $30$
Therefore, the other $30$ comprises solvent (which can be water, methanol or any other chemical substance).

Note:
There are some more concentration terms such as normality and molarity. We can define normality as the number of moles of solute that are present in one kilogram of the solvent and molarity is referred to as the number of moles (n) of solute that are present in one litre of the solution.