Rank the following compounds in order of reactivity toward nitration with HNO3:. thiophene, benzene, 3-methylthiophene, and 2-methylfuran.

3-methylthiophene > thiophene > benzene > 2-methylfuran

Explanation:

Primarily, five membered heterocyclic aromatic rings undergo nitration at carbon-2. This is because, nitration at carbon-2 leads to the formation of three resonance structures while attack at carbon-3 yields only two resonance structures, hence it is less stabilized.

The presence of a methyl group which donates electrons promotes the stabilization of the cation formed in the nitration of 3-methylthiophene.

2-methylfuran is the least reactive towards nitration because the 2-position has been blocked by a methyl group.

a  solution  is always transparent, light passes through with no scattering from solute particles which are molecule in size. the  solution  is homogeneous and does not settle out. a colloid is intermediate between asolution  and a  suspension. while asuspension  will separate out a colloid will not.