Compounds of Phosphorous- Phosphine

Let's discuss a gas that has the smell of rotten Fish.

The same gas is so poisonous that a small amount of it may cause death.

Also, this gas explodes if exposed to traces of nitric acid or chlorine.

The gas that we are talking about is Phosphine.

The chemical formula of Phosphine is .

Let us look at the methods of preparation of Phosphine.

Phosphine can be obtained by reaction of Calcium Phosphide with water or dilute HCl.

Another method of preparation of phosphine is heating white phosphorus with concentrated NaOH solution, in an inert atmosphere of .

Up next. let’s look at the properties of phosphine.

Phosphine is slightly soluble in water. This is because of its non polar P-H bonds.

And when dissolved in water, it decomposes in contact with light to give red phosphorus and .

Phosphine is a very weak base.

And on reaction with acids, it gives phosphonium compounds, just like ammonia.

Next phosphine undergoes reactions to form phosphides.

When phosphine is passed through copper sulphate or mercuric chloride solution, corresponding phosphides are formed.

Another interesting property of phosphine is its inflammable nature when in impure form.

In the impure form, inflammable vapours such as or are present along with phosphine.

However, it can be purified by absorbing phosphine in the presence of hydrogen iodide.

Phosphonium iodide formed is, then, treated with KOH to give pure Phosphine.

This pure phosphine formed is non inflammable in nature.

Finally, let us look at the uses of Phosphine.

The spontaneous combustion of phosphine is used in generating Holme’s signals mostly by sailors.

In this, the sailors throw pierced containers containing calcium carbide and calcium phosphide into the sea.

As we know, Calcium Phosphide reacts with water to give Phosphine.

This gas evolved then burns and serves as a signal.

Revision

The chemical formula of Phosphine is .

Phosphine can be obtained by reaction of Calcium Phosphide with water or dilute HCl.

When dissolved in water, it gives red phosphorus & in presence of light.

On reaction with acids, it gives phosphonium compounds.

The End !