Which of the following methods of expressing concentration are unitless?

The number of units,which are used to express the concentration of solutions from the following,is $.......$ Mass percent,Mole,Mole fraction,Molarity,ppm,Molality.

The molarity of the solution prepared by dissolving $6.3 \ g$ of oxalic acid $(H_{2}C_{2}O_{4} \cdot 2H_{2}O)$ in $250 \ mL$ of water in $mol \ L^{-1}$ is $x \times 10^{-2}$. The value of $x$ is ..... . (Nearest integer)
[Atomic mass : $H: 1.0, C: 12.0, O: 16.0]$

The molality of a $10\%\ (v/v)$ solution of di-bromine in $CCl_4$ (carbon tetrachloride) is $x$. $x = ...... \times 10^{-2}\ m$. (Nearest integer)
[Given : molar mass of $Br_2 = 160\ g\ mol^{-1}$
atomic mass of $C = 12\ g\ mol^{-1}$
atomic mass of $Cl = 35.5\ g\ mol^{-1}$
density of dibromine $= 3.2\ g\ cm^{-3}$
density of $CCl_4 = 1.6\ g\ cm^{-3}$]

How much water should be added to $200 \, cc$ of a semi-normal solution of $NaOH$ to make it exactly deci-normal?

$A$ solution contains $1 \ mole$ of water and $4 \ mole$ of ethanol. The mole fraction of water and ethanol will be