Question

Given, $15gram$ of methyl alcohol is dissolved in $35gram$ of water. What is the mass percentage of methyl alcohol in solution?
(A) $30\%$
(B) $50\%$
(C) $70\%$
(D) $75\%$

Answer 1

In order to answer this question, to find the mass percentage of methyl alcohol in solution, we will first find the total weight of the solution, as the weight of methyl alcohol and water is already given. And then we will find the mass percentage of methyl alcohol in the solution.

Complete answer:
According to the question, the given solution in which $15gram$ of methyl alcohol is dissolved in $35gram$ of water.
So, to find the mass percentage of methyl alcohol, first we need to find the total weight of the solution:-
Total weight of the solution $= (15g + 35g) = 50gram$
Now, we have the total weight of solution and the weight of methyl alcohol (given).
So now, we can find the mass percentage of methyl alcohol in solution:-
$\therefore$ Mass percentage of methyl alcohol
$= \dfrac{{weight\,of\,methyl\,alcohol}}{{total\,weight\,of\,solution}} \times 100 \\\ = \dfrac{{15}}{{50}} \times 100 = 30\% \\\$
Therefore, the required percentage of methyl alcohol in the solution is $30\%$ .
Hence, the correct option is (A) .

Note:
The term " $mass{\text{ }}per{\text{ }}cent$ " is used to represent a concentration or to describe a component in a combination. The mass percentage of solute present in a given mass of solution can be used to characterise the solution composition. The amount of solute is measured in mass or moles. The mass percent of a solution is calculated by multiplying the $grams{\text{ }}of{\text{ }}solute{\text{ }}per{\text{ }}gram$ of solution by 100 to get the percentage.