Calculate the mole fraction of benzene in a solution containing $30\%$ by mass in carbon tetrachloride.

The normality of $10 \%$ (weight/volume) acetic acid is ......... $N$.

$A$ sample of drinking water is found to be severely contaminated with chloroform $(CHCl_3)$,which is a suspected carcinogen. The level of contamination is $15 \ ppm$ (by mass). Calculate the molarity of chloroform in the water sample.

The molarity of $20\% \,(W/W)$ solution of sulphuric acid is $2.55 \, M$. The density of the solution is $........... \, g \, cm^{-3}$.

$3.0\, g$ of oxalic acid $[(CO_2H)_2 \cdot 2H_2O]$ is dissolved in a solvent to prepare a $250\, mL$ solution. The density of the solution is $1.9\, g/mL$. The molality and normality of the solution,respectively,are closest to

$34.2 \ g$ of sugar is dissolved in $1.8 \times 10^{2} \ g$ of water to form sugar syrup. Calculate the mole fraction of sugar. (Molar mass of sugar $= 342 \ g/mol$,water $= 18 \ g/mol$)