JEE Chemistry 2025 Question with Solution

Given: compound S is identified in the solution as $\mathrm{C_2H_6O}$ and the amount is $0.1$ mole.

Find: the mass of $0.1$ mole of S.

Use the relation

$$\text{Mass} = \text{moles} \times \text{molar mass}$$

First calculate the molar mass of $\mathrm{C_2H_6O}$:

$$(2 \times 12) + (6 \times 1) + (1 \times 16) = 24 + 6 + 16 = 46 \; \text{g mol}^{-1}$$

Now calculate the mass of $0.1$ mole:

$$0.1 \times 46 = 4.6 \; \text{g}$$

Therefore, $0.1$ mole of compound S weighs $4.6 \, \text{g}$.

Given: atomic masses are $\text{C} = 12$, $\text{H} = 1$, and $\text{O} = 16$.

Find: the weight of $0.1$ mole of compound S.

From the extracted solution, compound S is taken as $\mathrm{C_2H_6O}$.

Contribution of each element:

• Carbon: $2 \times 12 = 24$
• Hydrogen: $6 \times 1 = 6$
• Oxygen: $1 \times 16 = 16$

So,

$$\text{Molar mass of } \mathrm{C_2H_6O} = 24 + 6 + 16 = 46 \; \text{g mol}^{-1}$$

Then,

$$\text{Weight} = 0.1 \times 46 = 4.6 \; \text{g}$$

the solution also contains a conflicting alternate discussion, but it finally aligns with $4.6 \, \text{g}$. Hence the numerical answer is $4.6$.