Question

Give two reasons to justify
(a) Water at room temperature is a liquid
(b) An iron almirah is a solid at room temperature

Answer 1

Hint: The explanation of the above question is mentioned below-

(a) Water has the ability to form intermolecular H-bonding because of the presence of hydrogen atom and an electronegative atom i.e. oxygen

(b) Iron is a hard solid which has definite volume as well as definite shape. The melting point of iron is  $ {{1538}^{\text{o}}} $  while the room temperature is  $ 20-{{35}^{\text{o}}}\text{C} $ .

Complete step by step solution:

We can explain the above in the following points-

(a) Water at room temperature exists as liquid because its melting point is below room temperature while boiling point ( $ {{100}^{\text{o}}} $ C) is above room temperature. Similarly,

(i). A fixed mass of water occupies a fixed volume.

(ii). Water at room temperature does not have a fixed shape but flows to take the shape of the container.

Hence, water at room temperature is a liquid.

(b) An iron almirah is a solid at room temperature because its melting point as well as boiling point is above room temperature. Similarly,

(i) An iron almirah is rigid and has a fixed shape.

(ii) The density of metals is quite high.

Hence, iron almirah is a solid at room temperature.

Note: We should also know that,

For water: At 273K, water can exist in solid as well as in liquid state but liquid water will absorb latent heat of freezing and changes into solid state but solid ice can be directly used for cooling purposes as it will not absorb latent heat of freezing.

For iron: When a piece of iron is left out in the open for a while, a film of brownish substance gets deposited on its surface called rust. Rusting occurs when iron is exposed to oxygen in air and water or water vapor. Rust is iron oxide. Iron plus oxygen plus water vapor gives iron oxide.