The correct order of intensity of colors of the compounds is :

The set in which compounds have different nature is :

The species given below that does NOT show disproportionation reaction is :

Given below are two statements. One is labelled as Assertion A nd the other is labelled as Reason R.

Assertion A : Sharp glass edge becomes smooth on heating it upto its melting point.

Reason R : The viscosity of glass decreases on melting.

Choose the most appropriate answer from the options given below.