Which chemical property of potassium (K) distinguishes it from other alkali metals?

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Its higher density compared to sodium

Its ability to react with water at low temperatures

Its lower melting point than lithium

Its unique coloration in flame tests

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Answer

Potassium is the alkali metal with the lowest melting point, about 63 °C, which is lower than sodium’s 98 °C and much lower than the others. This means potassium can be melted with only a small amount of heat, unlike its heavier siblings that stay solid until much higher temperatures. Because of this, a pot of liquid potassium can be made at a relatively low temperature, which is useful for experiments that require a liquid alkali metal. For example, a laboratory can melt potassium in a small crucible using a simple hot plate, while sodium would need a hotter source. This distinctive melting behavior sets potassium apart from the other alkali metals.

Detailed Explanation

When potassium vapor is heated, it emits a light purple color in a flame test. Other options are incorrect because Density is not a distinguishing feature; All alkali metals react strongly with water, even at room temperature, and potassium is no exception.

Key Concepts

chemical properties

potassium (K)

Topic

Alkali Metals

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medium level question

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understand

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