Question

Chloroform with zinc dust in water gives
A. \[{\rm{C}}{{\rm{H}}_{\rm{4}}}\]
B. Chloropicrin
C. \[{\rm{CC}}{{\rm{l}}_{\rm{4}}}\]
D. \[{\rm{C}}{{\rm{H}}_{\rm{2}}}{\rm{C}}{{\rm{l}}_{\rm{2}}}\]

Answer 1

Hint: The reaction of chloroform with zinc dust in water is a reduction reaction. We know, a reduction reaction is the one in which the addition of hydrogen to a compound takes place. So, here, we have to find out the product which is formed after reduction.

Complete Step by Step Solution:
Let’s understand the reaction of zinc dust in the water. The reaction of zinc with water produces zinc hydroxide and nascent hydrogen. The chemical reaction is,
\[{\rm{Zn}} + {{\rm{H}}_{\rm{2}}}{\rm{O}} \to {\rm{Zn(OH}}{{\rm{)}}_2} + 2\left[ {\rm{H}} \right]\]

The nascent hydrogen undergoes reaction with chloroform. And this is the reduction reaction. The hydrogen atoms are added to the chloroform and the product formed are dichloromethane and hydrogen chloride .
\[{\rm{CHC}}{{\rm{l}}_{\rm{3}}} + 2\left[ {\rm{H}} \right] \to {\rm{C}}{{\rm{H}}_{\rm{2}}}{\rm{C}}{{\rm{l}}_{\rm{2}}} + {\rm{HCl}}\]
Hence, the option D is right.

Additional Information:
Let’s discuss some facts about chloroform. Chloroform whose chemical formula is \[{\rm{CHC}}{{\rm{l}}_{\rm{3}}}\] is a liquid of no colour. It undergoes evaporation to gaseous forms very quickly. Exposure to chloroform causes harmful effects on the eyes, kidneys, liver, and nervous system. If it is swallowed or inhaled, it can be toxic. Also, exposure to chloroform causes cancer. In the laboratory, chloroform is mainly used as a solvent. A solvent is a substance that helps to dissolve other substances.

Note: Zinc dust is an important reagent of organic chemistry. It acts as a reducing agent. A reducing agent is one that helps in the addition of hydrogen to a compound. It is to be noted that zinc dust or powders are finely divided substances of zinc metal.