$A$ mixture of alcohol and water contains $54 \%$ water by mass. What is the mole fraction of ethanol?

$10.6 \, g$ of a substance of molecular weight $106$ was dissolved in $100 \, mL$. $10 \, mL$ of this solution was pipetted out into a $1000 \, mL$ flask and made up to the mark with distilled water. The molarity of the resulting solution is

The molality of a solution is defined as:

$200 \ g$ of $20 \% \text{ } w/w$ urea solution is mixed with $400 \ g$ of $40 \% \text{ } w/w$ urea solution. What is the weight percentage $(w/w \%)$ of the resultant solution (in $.33$)?

When $6 \ g$ of urea is dissolved in $180 \ g$ of $H_2O$,the mole fraction of urea is:

The mole fraction of glucose $(C_{6}H_{12}O_{6})$ in an aqueous binary solution is $0.1$. The mass percentage of water in it,to the nearest integer,is $....$.