NCERT Question 5 - Chapter 1 Class 9 - Matter In Our Surroundings

What is the physical state of water at—

(a) 25°C (b) 0°C (c) 100°C ?

Answer

We know that

Physical state of Water at temperatures

• 0° C or less - Ice (Solid) 
• 0° C to 100° C - Water (Liquid) 
• 100° C or above - Steam(Gas) 

Thus, Physical state of water at

1. 25° C - Liquid state 
2. 0° C - 0° C is the freezing point of water. Hence, at 0° C water exists in both liquid (water) and solid (water vapour) states. 
3. 100° C - 100° C is the boiling point of water. Hence, at 100° C water exists in both liquid (water) and gaseous (water vapour) states.