Question

The oxidation state of phosphorus is minimum in:
   A. \[{P_4}{O_6}\]
   B. $N{a_2}{H_2}P{O_2}$
   C. $P{H_3}$
   D. $N{a_3}P{O_4}$

Answer 1

Hint: We will write about what is given in the question. Then we will see what oxidation state means. Then we will know what the oxidation state of phosphorus is in each option. We will check which the minimum oxidation number of phosphorus is. In the end we will choose the correct option.


Complete solution:
Step1. We are given the four options with phosphorus in them. We need to find the minimum oxidation number of the phosphorus in all of those.
Step2. The oxidation number is the number of electrons that an atom can lose, share or gain while forming the chemical bond with other atoms. The oxygen number is often used in coordination compounds. It appears when the atoms react with other hetero atoms.
Step3. In option \[{P_4}{O_6}\]the total charge is zero. The total charge over oxygen would be $ - 12$ so to neutral it we need the oxidation number of phosphorus to be positive three. It would neutralize the negative twelve of oxygen.
Step4. The oxygen number of Phosphorus in phosphine $P{H_3}$ is $ - 3$ because the hydrogen is having a total of plus three so the phosphorus $ - 3$ will neutralize it. All others have positive oxidation numbers.
Step5. Hence the Option C is the correct answer which is $P{H_3}$.

So, clearly we can conclude that the correct answer is Option C.


Note:. Phosphine is a colourless gas. It has a foul smell. It is flammable and highly explosive. It is used as an insecticide for the fumigation of grains and animal feed. It is dangerous for health in the short term. We must not inhale it.