Question

Phosphine is obtained from the following ore
A. Calcium superphosphate
B. Calcium phosphide
C. Potassium phosphide
D. Calcium hypophosphite

Answer 1

Hint: Phosphine is a colourless gas with a bad fish-like smell and is highly harmful. The chemical formula of phosphine is \[{\rm{P}}{{\rm{H}}_{\rm{3}}}\]. It is highly toxic for respiration and is fatal if consumed at more than 50 ppm. It has a pyramidal structure.

Complete Step by Step Solution:
Phosphine explodes in touch with traces of oxidising agents like nitric acid, chlorine, and bromine vapours. It is a little soluble in water. The solution of phosphine in water breaks down in the existence of light producing red phosphorus and Hydrogen gas. It is furnished by the reaction of calcium phosphide with water or diluted hydrochloric acid. Calcium Phosphide has a reddish-brown colour and is a crystalline granular solid.

The reaction happens as follows:
\[{\rm{C}}{{\rm{a}}_{\rm{3}}}{{\rm{P}}_{\rm{2}}}{\rm{ + 6}}{{\rm{H}}_{\rm{2}}}{\rm{O}} \to {\rm{3Ca}}{\left( {{\rm{OH}}} \right)_{\rm{2}}}{\rm{ + 2P}}{{\rm{H}}_{\rm{3}}}\]
\[{\rm{C}}{{\rm{a}}_{\rm{3}}}{{\rm{P}}_{\rm{2}}}{\rm{ + 6HCl}} \to {\rm{3CaC}}{{\rm{l}}_{\rm{2}}}{\rm{ + 2P}}{{\rm{H}}_{\rm{3}}}\]

Calcium hydroxide and calcium chloride are formed as side products. This compound when in contact with acids or water, releases phosphine, which is harmful and is readily burned. So, safety measures are taken to store this compound.
So, option B is correct.

Additional Information: Calcium phosphide's industry name is Photophor for its usage as an inflammatory. It is also called Polytanol for its usage as a rodenticide. Rodenticide means the chemicals created and traded for the objective of killing rodents. It is also cited as rat poison. These rodenticides are also used to kill mice, squirrels, etc.

Note: The involuntary explosion of phosphine is utilised in Holme’s
signals. Vessels containing calcium carbide and calcium phosphide are penetrated and thrown into the sea when the gases start to burn and perform as a signal. It is also used in smoke screens.