Why dilute H₂SO₄ cannot be used for the laboratory preparation of carbon dioxide?

Why is it dangerous to sleep in a closed room in which coal is burning ?

Explain the following phenomenon by means of balanced equations:
(i) When exhaling is made through a tube passing into a solution of lime water, solution becomes turgid. 
(ii) The turbidity of the above solution. 
(iii) eventually disappears when continued exhaling is made through it.

154.

What is dry ice? Why is it so called?

How is excessive content of CO₂ responsible for global warming? 

Write the resonance structures of 

What is the state of hybridization of carbon in (a)  (b) diamond (c) graphite?

Explain why silicon tetrachloride is hydrolyzed but carbon tetrachloride is not hydrolysed.

Contrast the structure and properties of CO₂ and SiO_2.