Question

If a substance ‘A’ dissolves in a solution of a mixture of ‘B’ and ‘C’ with their respective number of moles as $n_a$, $n_b$, and $n_c$, the mole fraction of C in the solution is:

• A. \frac{n_C}{n_A + n_B + n_C} \\\
• B. $\frac{n_C}{n_A \times n_B \times n_C}$
• C. \frac{n_C}{n_A - n_B - n_C} \\\
• D. \frac{n_B}{n_A + n_B} \\\

Answer 1

Answer: (A)

\frac{n_C}{n_A + n_B + n_C} \\\

Answer 2

Solution: The mole fraction of a component in a solution is defined as the ratio of the number of moles of that component to the total number of moles of all components in the solution.

Calculating Mole Fraction of C: Given that the moles of substances are $n_a$, $n_b$, and $n_c$, the total number of moles in the solution is:

$n_a + n_b + n_c$.

The mole fraction of substance $C$ can be calculated as follows:

$\text{Mole fraction of } C = \frac{n_c}{n_a + n_b + n_c}$.

Conclusion: Therefore, the mole fraction of $C$ in the solution is given by option (1): $\frac{n_c}{n_a + n_b + n_c}$.