We have a large number of organic compounds. Due to which of the following property ot carbon is this possible? 

When water gas is mixed with half its volume of hydrogen and the mixture is compressed 300 atmospheric pressure and passed over $\mathrm{ZnO}.{\mathrm{Cr}}_2{\mathrm{O}}_3$ catalyst a colourless liquid is obtained which is used as a solvent for paint and varnishes. The liquid will be 

Identify the correct order of boiling points of the following compounds 

(A) ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{OH}$

(B) ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{CHO}$

(C) ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{COOH}$

Give one phrase for the following statement:

The tendency of an element to form chains of identical atoms.

Give two examples of synthetic carbon compounds.