Draw electron dot structure of propanoic acid.

Complete the following reaction:

${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}\stackrel{\mathrm{Alkaline} {\mathrm{KMnO}}_4}{\to }$ 

Complete the following reaction:

${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}+\mathrm{Na}\to$ 

Complete the following reaction:

${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}+{\mathrm{O}}_2\to$

An organic compound 'A' is widely used as a preservative in pickles and has a molecular formula ${\mathrm{C}}_2{\mathrm{H}}_4{\mathrm{O}}_2$. The compound reacts with ethanol to form a sweet smelling compound 'B'.

(i) Identify the compound 'A'. 
(ii) Write the chemical equation for its reaction with ethanol to form compound 'B'.
(iii) How can we get compound 'A' back from 'B'? 
(iv) Which gas is produced when compound 'A' reacts with washing soda? Write the chemical equation. 

(a) Why does carbon form largest number of compounds?
(b) Why are some of these called saturated while other unsaturated compounds?
(c) Which of these two are more reactive?