Question

1.0 g of a non- volatile solute was dissolved in 100 g of acetone (mol. mass = 58) at 298 K. The vapor pressure of the solution was found to be 192.5 mm Hg. The molecular mass of the solute is: (Vapor pressure of acetone = 195 mm Hg)

Answer 1

The term "nonvolatile" refers to a substance that has little tendency to evaporate. Some of the solvent particles in the right-hand solution have been replaced with solute particles. The vapor pressure of the solution is lower than that of the pure solvent because the solute particles do not evaporate.

Complete answer:
Solute – A solute is a material that is dissolved in a solution. The amount of solvent in a fluid solution is more than the amount of solute. Salt and water are two of the most common examples of solutes in our daily lives. Because salt dissolves in water, it is the solute.
Solvent - A solvent is a substance that dissolves a solute and forms a solution as a result. A liquid is the most common type of solvent, although it can also be a solid, a gas, or a supercritical fluid. Water is the most frequent solvent utilized by living organisms and a solvent for polar molecules; all ions and proteins in a cell are dissolved in water within the cell.
Molecular mass- The mass of a molecule is measured in moles (m). Because they contain various isotopes of an element, different molecules of the same substance may have different molecular weights. The related quantity relative molecular mass is a unitless ratio of a molecule's mass to the unified atomic mass unit, as defined by IUPAC.
Roults law - Raoult's law is a physical chemistry law with thermodynamic consequences. The partial pressure of each component in an ideal mixture of liquids is equal to the vapor pressure of the pure component multiplied by its mole fraction in the mixture, according to a formula devised by French chemist François-Marie Raoult in 1887. As a result, the mole fraction of nonvolatile solute in a dilute solution lowers the vapor pressure compared to the mole fraction of solute in the solution.
$\ Mass{\kern 1pt} {\kern 1pt} {\kern 1pt} of{\kern 1pt} {\kern 1pt} {\kern 1pt} solute = 1g \\\ Mass{\kern 1pt} {\kern 1pt} {\kern 1pt} of{\kern 1pt} {\kern 1pt} {\kern 1pt} solvent = 100g \\\ Acetone{\kern 1pt} {\kern 1pt} {\kern 1pt} Molar{\kern 1pt} {\kern 1pt} mass{\kern 1pt} {\kern 1pt} = 58g/mole \\\ Vapour{\kern 1pt} {\kern 1pt} {\kern 1pt} pressure{\kern 1pt} {\kern 1pt} {\kern 1pt} pure{\kern 1pt} {\kern 1pt} {\kern 1pt} solvent{\kern 1pt} {\kern 1pt} {\kern 1pt} P_A^0{\kern 1pt} = 195{\kern 1pt} {\kern 1pt} {\kern 1pt} mm{\kern 1pt} {\kern 1pt} of{\kern 1pt} {\kern 1pt} Hg \\\ From{\kern 1pt} {\kern 1pt} {\kern 1pt} Roults{\kern 1pt} {\kern 1pt} {\kern 1pt} law \\\ \dfrac{{P_A^0 - {P_A}}}{{P_A^0}} = {X_B} \\\ \dfrac{{192 - 192.5}}{{192}} = \dfrac{{{n_B}}}{{{n_A}}} = \dfrac{{{w_B}}}{{{M_B}}} \times \dfrac{{{M_A}}}{{{w_A}}} \\\ 0.013 = \dfrac{{1 \times 58}}{{{M_B} \times 100}} \\\ {M_B} = \dfrac{{58}}{{0.013}} = 44.61 \\\ \$
So, the final answer i.e., the molecular mass of solute is 44.61g.

Note:
The mass of an atom is its atomic mass. Although the kilogram (symbol: kg) is the SI unit of mass, the atomic mass is sometimes stated in the non-SI unit Dalton, which is defined as 1/12 of the mass of a single carbon-12 atom at rest. The nucleus' protons and neutrons account for virtually all of an atom's total mass, with electrons and nuclear binding energy playing a modest role.