The number of molecules present in $100 \ mL$ of a urea solution is $6.02 \times 10^{23}$. What is the molarity $(M)$ of the urea solution?

$A$ solution is obtained by mixing $300 \, g$ of $25 \%$ solution and $400 \, g$ of $40 \%$ solution by mass. Calculate the mass percentage of the resulting solution. (in $\%$)

What will be the volume of a $12 \; M$ solution,if it is equivalent to $240 \; mL$ of an $18 \; M$ solution? (Express the answer in $litre$)

If $5.85 \ g$ of $NaCl$ is dissolved in $72 \ g$ of water,find the mole fraction of $NaCl$.

Calculate the molality of $1 \ L$ solution of $93 \ \%$ $H_2SO_4$ (weight/volume). The density of the solution is $1.84 \ g/mL$.

$x \ g$ of water is mixed in $69 \ g$ of ethanol. The mole fraction of ethanol in the resultant solution is $0.6$. What is the value of $x$ in grams?