Given below are two statements:Statement I: Sublimation is a purification technique that is used to separate those solid substances which change from solid to vapour state without passing through liquid state.
Statement II: If external atmospheric pressure is reduced, then boiling point of a substance is decreased.
In the light of the above statements, choose the correct option.
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At high altitudes, water boils at a lower temperature due to reduced atmospheric pressure.
Statement I is correct but statement II is incorrect
Statement I is incorrect but statement II is correct
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The Correct Option isA
Solution and Explanation
To determine the correctness of the given statements, we need to understand the concepts of sublimation and the effect of atmospheric pressure on the boiling point.
Statement I: "Sublimation is a purification technique that is used to separate those solid substances which change from solid to vapour state without passing through liquid state."
This statement is correct. Sublimation is indeed a process where a solid changes directly into vapor without passing through the liquid phase. This property is utilized for purifying substances like iodine, camphor, and naphthalene, which sublime under certain conditions.
Statement II: "If external atmospheric pressure is reduced, then the boiling point of a substance is decreased."
This statement is also correct. The boiling point of a substance is the temperature at which its vapor pressure equals the external pressure. When the atmospheric pressure is reduced, less heat is required for the vapor pressure to match the external pressure, thus lowering the boiling point.
Based on the above analyses, both statements are correct.
Therefore, the correct option is: Both statement I and statement II are correct.
