If one mole of a substance is present in $1 \ kg$ of solvent,then

If the mole fraction of ethanol in a solution formed by mixing $x \, g$ of water and $69 \, g$ of ethanol is $0.6$,then $x =$ ...... $g$.

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

$25.3 \ g$ of sodium carbonate,$Na_2CO_3$ is dissolved in enough water to make $250 \ mL$ of solution. If sodium carbonate dissociates completely,the molar concentration of sodium ions,$Na^{+}$,and carbonate ions,$CO_3^{2-}$,are respectively:
(Molar mass of $Na_2CO_3 = 106 \ g \ mol^{-1}$)

What is the mole fraction of water in a spirit sample containing $92 \%$ ethyl alcohol by weight?

An aqueous $KCl$ solution of density $1.20 \ g \ mL^{-1}$ has a molality of $3.30 \ mol \ kg^{-1}$. The molarity of the solution in $mol \ L^{-1}$ is ..... . (Nearest integer)
[Molar mass of $KCl = 74.5 \ g \ mol^{-1}$]