Question

Which of the following substance exists in gaseous form at room temperature?

• A. Water
• B. Chalk
• C. Oxygen
• D. Iron

Answer 1

The correct option is C Oxygen

There are three states of mater - solid, liquid and gas.​

• Solids are the matter that have definite shape and definite volume.​
• Liquids are the matter that have indefinite shape but definite volume.​
• Gases are the matter that have indefinite shape as well as indefinite volume.​

Out of the given options, chalk and iron are solids at room temperature as they have definite shape and volume. Water is liquid at room temperature as it has indefinite shape, but definite volume and oxygen is the gas since it has indefinite shape and volume. ​