Which of the following methods of expressing concentration are unitless?

What type of solution is an alloy?

Which of the following modes of expressing concentration is independent of temperature?

Commercially available $H_2SO_4$ is $98 \ g$ by weight of $H_2SO_4$ and $2 \ g$ by weight of water. Its density is $1.38 \ g \ cm^{-3}$. Calculate the molality $(m)$ of $H_2SO_4$ (molar mass of $H_2SO_4$ is $98 \ g \ mol^{-1}$). (in $m$)

If $5.0 \ g$ of $BaCl_2$ is present in $10^6 \ g$ solution,the concentration is .......... $ppm$.

If a solution is $98\% \ H_2SO_4$ by weight and has a density of $1.8 \ g/mL$,its molarity is ....... $M$.