Question

Mole fraction of ethyl alcohol in aqueous ethyl alcohol \[\left( {{C}_{2}}{{H}_{5}}OH \right)\]solution is \[0.25\]. Hence percentage of ethyl alcohol by weight is:
A. \[54%\]
B. \[25%\]
C. \[75%\]
D. \[46%\]

Answer 1

Hint: Mole portion speaks to the quantity of atoms of a specific part in a blend isolated by the all out number of moles in the given combination. It's a method of communicating the convergence of an answer. Mole Fraction formula, the molar part can be spoken to by X.

Complete step by step answer:
In chemistry, the mole fraction or molar fraction is defined as the unit of the amount of a constituent (expressed in moles), divided by the total amount of all constituents in a mixture (also expressed in moles).
Percent by mass (percent by weight) is the percent of the total mass of the solution that is one component. Percent by mass = mass fraction\[\times 100\].
If ethanol is \[0.25\], then \[{{H}_{2}}O\] will be \[0.75\].
Weight of ethanol is \[46.06\,g/mol,\]
\[0.25\,mol=11.515\,g\] of ethanol,
Weight of \[{{H}_{2}}O\] is \[18.01528\,g/mol,\]
So, \[0.75\,mol=13.51\,g\] of \[{{H}_{2}}O\]
Total weight \[=25.02646\,g\]
Weight percentage of ethanol is
\[=\dfrac{11.515}{25.02646}\times 100=46.011\approx 46%\]

Hence, the correct option is D. \[46%\]

Additional Information:
Ethanol is a significant mechanical substance; it is utilized as a dissolvable, in the amalgamation of other natural synthetics, and as an added substance to car gas (shaping a blend known as a gasohol). Ethanol is likewise the inebriating element of numerous mixed drinks, for example, brew, wine, and refined spirits.

Note:
To decide the weight percent of an answer, partition the mass of solute by mass of the arrangement (solute and dissolvable together) and duplicate by 100 to acquire percent.