$3.1 \ g$ of a compound,'$X$' (molar mass $= 62 \ g \ mol^{-1}$) is dissolved in $19.5 \ g$ of other compound,$Y$ (molar mass $= 78 \ g \ mol^{-1}$). The ratio of mole fractions of $X$ and $Y$ in the solution is

The molarity of pure water is $......$

The mole fraction of urea in an aqueous urea solution containing $900 \text{ g}$ of water is $0.05$. If the density of the solution is $1.2 \text{ g cm}^{-3}$,the molarity of the urea solution is . . . . . (Given data: Molar masses of urea and water are $60 \text{ g mol}^{-1}$ and $18 \text{ g mol}^{-1}$,respectively)

The molecular weight of glucose is $180$. $A$ solution of glucose which contains $18 \ g$ per litre is ........... $molal$.

The molarity of a solution containing $15 \text{ g}$ of $\text{NaOH}$ in $900 \text{ ml}$ of solution will be . . . . . . . (in $\text{ M}$)

$30 \ mL$ of $0.5 \ M$ $NaOH$ is diluted to $500 \ mL$ by adding water. What will be the molarity of the diluted solution (in $M$)?