Question

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Answer 1

Liquid element :

Only two elements are liquid at standard conditions for temperature and pressure: mercury and bromine. Four more elements have melting points slightly above room temperature: francium, caesium, gallium and rubidium.

Nobel metals :

Noble metal (gold, platinum, palladium, silver, rhodium, and ruthenium) and transition-metal (iron, nickel, copper) NPs are used in different catalytic reactions.

Gas in gas :

• Hydrogen.
• Nitrogen.
• Oxygen.
• Carbon Dioxide.
• Carbon Monoxide.
• Water Vapour.