During the pyrolysis of alkanes C-C bonds break in preference to C-H bond. Why?

Define cracking. 

Arrange the following compounds in order of their increasing boiling points:
n-Pentane, n-Hexane, Ethane, 2-2-Dimethylpentane, 2-Methylpentane.

Alkanes are less reactive. Why?

What is the function of iodic acid in the iodination of alkanes? Can we use any other substance in its place?

Name the metal which is a constituent of Grignard's reagent.

What is alternation effect?

Out of n-pentane, isopentane and neopentane which has lower boiling point?

Name the products formed when an ethereal solution containing ethyl iodide and methyl iodide is heated with sodium metal.