An aqueous solution is 1.00 molal in KI. Which change will cause the v...
Addition of water
Vapour pressure depends upon the surface area of the solution. Larger the surface area, higher is the vapour pressure.
The addition of solute decreases the vapour pressure as some sites of the surface are occupied by solute particles, resulting in decreased surface area. However, the addition of solvent, ie, dilution increases the surface area of the liquid surface, thus results in increased vapour pressure.
Hence, the addition of water to the aqueous solution of (1 molal) KI, result in increased vapour pressure.
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An aqueous solution is 1.00 molal in KI. Which change will cause the v...
Explanation:
1. Molality:
Molality (m) is defined as the number of moles of solute per kilogram of solvent. It is a measure of the concentration of a solute in a solution.
2. Vapour Pressure:
Vapour pressure is the pressure exerted by the vapour phase of a substance when it is in equilibrium with its liquid or solid phase at a given temperature. It depends on the concentration of the solute in the solution.
3. Effect of Adding Water:
When water is added to the solution, the total concentration of the solution decreases. This means that the molality of KI in the solution will also decrease. As a result, the vapour pressure of the solution will increase.
4. Effect of Adding NaCl:
Adding NaCl does not directly affect the concentration of KI in the solution. Therefore, it will not have a significant effect on the vapour pressure of the solution.
5. Effect of Adding Na2SO4:
Similar to NaCl, adding Na2SO4 does not directly affect the concentration of KI in the solution. Thus, it will not have a significant effect on the vapour pressure of the solution.
6. Effect of Adding 1.0 molal KI:
Adding more KI to the solution will increase the concentration of KI in the solution. However, the question states that the solution is already 1.00 molal in KI. Therefore, adding more KI will not change the concentration significantly and will not have a significant effect on the vapour pressure of the solution.
Overall, adding water to the solution will decrease the concentration of KI and increase the vapour pressure of the solution. Therefore, the correct answer is option 'A': Addition of water.