The number of gram molecules of a substance present in unit volume is termed as

When $7.1 \ g$ of $Na_2SO_4$ (molecular mass $142$) dissolves in $100 \ mL$ of $H_2O$,the molarity of the solution is $.........$ $M$.

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)

Which among the following is a unitless physical quantity?

When $W_B \ g$ of solute (molecular mass $M_B$) is dissolved in $W_A \ g$ of solvent,the molality $m$ of the solution is:

The mole fraction of water in a $20\%$ aqueous solution of $H_2O_2$ is: