Question

Aromatic compounds burn with sooty flame. The flame is less sootier than alkenes.
(A) True
(B) False

Answer 1

Hint: When organic compounds burn, the color and sooty flame depends on the carbon content. More the carbon content, the more yellowish the flame is and there are black fumes present.

Complete Step by step solution:
An alkene is a hydrocarbon that contains a carbon-carbon double bond and they are often called olefin. For one double bond in a compound, we name it as alkene, for two double bonds we name it as alkadiene, for three double bonds we name it alkatriene, for many double bonds we name it polyene. The carbon content of alkene is less with respect to the other organic compounds like aromatic.
Aromatic compounds are chemical compounds that consist of delocalized pi-electron clouds in place of individual alternating double bonds, single bonds and they consist of conjugated planar ring systems. They are also called aromatics or arenes. Aromatic compounds need to satisfy Huckel’s rule. By Huckel's rule, we estimate whether a planar ring molecule will have aromatic properties or not. Huckel's rule says that for a compound to be aromatic it should have the following properties,
Planarity
Presence of $ \left( {4n + 2} \right)\pi $ electrons in the ring where n is an integer (n = 0, 1, 2, . . .)
Complete delocalization of the $ \pi $ electrons in the ring.
Examples of aromatic compounds are benzene, naphthalene.
When an organic compound is being burned the color of the flame depends on the carbon compound being used. When saturated hydrocarbons are being burned, they give a clean flame but when unsaturated hydrocarbons are burned, they produce a yellow flame with black smoke. The burning of carbon ultimately gives a sooty deposit on the surface. Due to high concentration of carbon a lot of unburnt carbon is left leading to small particles in flame called as soot.
Aromatic compounds have more carbon content as compared to alkene. Therefore, when aromatic compounds are burned, they give a sootier flame than alkenes.
So, the above given statement is false.
True statement is: Aromatic compounds burn to give sootier flame than alkenes.

Note:
Alkenes burn with a sootier flame in comparison with alkanes. Alkanes are saturated hydrocarbons therefore there is less formation of soot. The lesser the number of hydrogens in the compound, more sootier shall be the flame.