When substance $A$ is dissolved in solvent $B$,it associates to form $A_3$. The van't Hoff factor $i$ is:

$A$ molecule $M$ associates in a given solvent according to the equation $M \rightleftharpoons (M)_n$. For a certain concentration of $M,$ the van't Hoff factor was found to be $0.9$ and the fraction of associated molecules was $0.2.$ The value of $n$ is

Determination of the molar mass of acetic acid in benzene using freezing point depression is affected by

The experimentally determined molar mass of a non-volatile solute,$BaCl_2$,in water by Cottrell's method,is

Molecules of benzoic acid $(C_6H_5COOH)$ dimerise in benzene. '$w$' $g$ of the acid dissolved in $30 \ g$ of benzene shows a depression in freezing point equal to $2 \ K.$ If the percentage association of the acid to form dimer in the solution is $80,$ then $w$ is : ............. $g$
(Given that $K_f = 5 \ K \ kg \ mol^{-1},$ Molar mass of benzoic acid $= 122 \ g \ mol^{-1}$ )

$1.2 \ g$ of $NaCl$ solution is isotonic with $7.2 \ g$ of glucose solution. Calculate the van’t Hoff factor $(i)$ of the $NaCl$ solution.