Question

One mole of component \(X\) and two moles of component \(Y\) are mixed at room temperature to form an ideal binary solution. The \(\Delta H_{mix}\) is

• A. \(0\)
• B. \(2\)
• C. \(3\)
• D. \(1\)

Hint:

For an ideal solution: \[ \Delta H_{mix}=0,\qquad \Delta V_{mix}=0 \]

Answer 1

The Correct Option is A

Concept:
An ideal solution is a solution that obeys Raoult's law over the entire range of concentration. For an ideal solution: \[ \Delta H_{mix}=0 \] and \[ \Delta V_{mix}=0 \] This means no heat is evolved or absorbed during mixing, and there is no volume change during mixing.

Step 1: Understand ideal solution.
In an ideal solution, interactions between unlike molecules are similar to interactions between like molecules. That means: \[ X-X,\quad Y-Y,\quad X-Y \] interactions are nearly equal.

Step 2: Effect on enthalpy of mixing.
Since the intermolecular attractions do not change significantly after mixing, there is no net heat change. Therefore: \[ \Delta H_{mix}=0 \]

Step 3: Apply to the given mixture.
The question says \(X\) and \(Y\) form an ideal binary solution. The number of moles given does not change the ideal solution property. So: \[ \Delta H_{mix}=0 \]

Step 4: Check the options.
Option (A) \(0\) is correct.
Option (B), (C), and (D) are incorrect because ideal solution has zero enthalpy of mixing. Hence, the correct answer is: \[ \boxed{(A)\ 0} \]