Which one of the following pairs of elements is liquid at room temperature and at normal pressure ?

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Q: 55 (NDA-II/2021)

Which one of the following pairs of elements is liquid at room temperature and at normal pressure ?

question_subject: 

Science

question_exam: 

NDA-II

stats: 

0,13,16,5,18,5,1

keywords: 

{'gallium': [0, 0, 0, 1], 'elements': [0, 0, 2, 5], 'mercury': [0, 0, 2, 2], 'caesium': [0, 0, 0, 7], 'bromine': [1, 1, 1, 3], 'room temperature': [0, 0, 5, 6], 'normal pressure': [0, 0, 0, 1]}

Option 1: Gallium and Bromine

Gallium is a solid at room temperature and normal pressure, with a melting point of 30 degrees Celsius. Bromine, on the other hand, is a liquid at room temperature and normal pressure, with a boiling point of 59 degrees Celsius. Therefore, this pair is incorrect as gallium is not liquid.

Option 2: Mercury and Bromine

Mercury is a liquid at room temperature and normal pressure, with a melting point of -38.8 degrees Celsius. Bromine is also a liquid at room temperature and normal pressure, with a boiling point of 59 degrees Celsius. Therefore, this pair is correct as both elements are liquid.

Option 3: Gallium and Mercury

As mentioned earlier, gallium is a solid at room temperature and normal pressure, and mercury is a liquid at room temperature and normal pressure. Therefore, this pair is incorrect as gallium is not liquid.

Option 4: Gallium and Caesium

Gallium is a solid at room temperature and normal pressure, and caesium is a solid as well, with a melting point of 28.5 degrees Celsius. Therefore, this pair is incorrect as both elements are solids.

Based on the analysis above, option