Tag: world energy needs

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Questions Related to world energy needs

Multiple choice chemistry world energy needs coal petroleum non-renewable sources of energy

Coal tar is the main source of:

  1. aromatic compounds

  2. alicyclic compounds

  3. aliphatic compounds

  4. nitro compounds
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Coal tar is a complex mixture of phenols, polycyclic aromatic hydrocarbons (PAHs), and heterocyclic compounds but it is mainly used as the main source for aromatic compounds.

Multiple choice chemistry world energy needs coal petroleum non-renewable sources of energy

When fractional distillation of coal tar is carried out, the percentage of which fraction is maximum?

  1. Pitch

  2. Gasoline

  3. Lubricating oil

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When fractional distillation of coal tar is carried out,  the maximum percentage is of pitch. Pitch is undistilled residue. It is about 50-60%.

Multiple choice chemistry world energy needs coal petroleum non-renewable sources of energy

When a fractional distillation of coal tar is carried out, the percentage of which fraction is minimum?

  1. Light oil or crude naphtha

  2. Middle oil or carbolic oil

  3. Heavy oil or creosote oil

  4. Green oil or anthracene oil
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

During the fractional distillation of coal tar, the fraction which has minimum percentage is light oil or crude naphtha. It is obtained only $1.5-2\%$ in the distillation.

Multiple choice chemistry world energy needs coal petroleum non-renewable sources of energy

Separation of two substances by crystallisation depends upon their differences in:

  1. densities

  2. solublity

  3. melting point

  4. boiling point
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Separation of $2$ substances by crystallization depends upon their difference in solubility as more soluble impurity will go into the solution and less soluble component will crystallize out.