Give reasons (a) A gas fills completely the vessel in which it is kept. (b) A gas exerts pressure on the walls of the container.

Question 3. Give reasons                                                                                          
(a) A gas fills completely the vessel in which it is kept.                                
(b) A gas exerts pressure on the walls of the container.                              
(c) A wooden table should be called a solid.                                                
(d) We can easily move our hand in air but to do the same through a solid block of wood we need a karate expert.
Answer:

(a) A gas fills completely the vessel in which it is kept because the particles of gas move freely and acquire the shape of the container.
(b) A gas exerts pressure on the walls of the container because particles of gas move freely and randomly due to which they hit the boundaries of the container and exert the force on its wall.
(c) A wooden table has a definite shape and definite volume and hence it is called solid.
(d) We can easily move our hand in air but to do the same through a solid block of wood we need a karate expert because there is lot of empty space between the particles of gas but it not so in case of solids.