The image below shows the boiling point of first seven straight chain primary alcohols and first seven straight chain primary alkanes.

The boiling point of both the series increase monotonically with increasing size of the molecules. However, the slope of increment is different for both the series.
Observe the above graph and answer the following questions:
(i) Why are the boiling point of alcohols higher than that of corresponding alkanes?
(ii) Why do the differences in boiling point between corresponding alcohols and alkanes get less as the number of carbon atoms increase?
(iii) Can the two graphs ever intersect?
(iv) Will the graph look like almost the same if boiling point is replaced with melting point?
(v) How will the boiling point graph for straight chain primary amines fare as compared to alcohols and alkanes?