41.
The first organic compound synthesised in the laboratory was

42.
Among the following, carbonate ore of Zinc is

43.
The metal used for making aircrafts and rockets is

44.
The compound that has the least value for octane number is :

45.
The length of double bond is _______ than single bond.

46.
An example of heterocyclic compound is

47.
In organic compounds, nitrogen is estimated by

48.
Heavy metals got their name because compared to other atoms they have

49.
Which one of the following elements exhibits the greatest tendency to lose electrons ?

50.
Which one is heaviest naturally occurring element of the periodic element?