Question

Which of the given compounds burn with a sooty flame? Naphthalene, Ethanol, Butane

Answer 1

Part 1: Naphthalene (${\mathbf{C}}_{\mathbf{10}}{\mathbf{H}}_{\mathbf{8}}$)

1. Unsaturated Carbon compounds don't burn fully and give a sooty flame with unburnt or partially burnt Carbon particles.
2. An Unsaturated hydrocarbon having a double bond between two adjacent Carbon- Carbon atoms (C=C) is indicated by writing the word “ene” after the stem, then it should be an Alkene.
3. Naphthalene (${\mathbf{C}}_{\mathbf{10}}{\mathbf{H}}_{\mathbf{8}}$) come under the unsaturated hydrocarbon due to the fact they form a double bond.
4. Hence, this will give a sooty flame.

Part 2: Butane (${\mathbf{C}}_{\mathbf{4}}{\mathbf{H}}_{\mathbf{10}}$)

1. A saturated hydrocarbon having a single bond between two adjacent Carbon- Carbon atoms (C-C) is indicated by writing the word “ane” after the stem, then it should be an Alkane.
2. Butane (${\mathbf{C}}_{\mathbf{4}}{\mathbf{H}}_{\mathbf{10}}$) is an example of a saturated hydrocarbon.
3. Hence, this will not give a sooty flame.

Part 3: Ethanol (${\mathbf{C}}_{\mathbf{2}}{\mathbf{H}}_{\mathbf{5}}\mathbf{OH}$)

1. Ethanol is having chemical formula ${\mathbf{C}}_{\mathbf{2}}{\mathbf{H}}_{\mathbf{5}}\mathbf{OH}$.
2. Ethanol consists of a single bond between two adjacent Carbon- Carbon atoms (C-C). Thus, it is also a saturated hydrocarbon.
3. Hence, this will not give a sooty flame.