`text(Preparation of)` `PH_3` `text((Phosphine Gas))`

(i) `4H_3PO_3 overset(Delta)-> PH_3 +3H_3PO_4`

(ii) `underset(PH_3 + HI)(PH_4I) + KOH -> KI + PH_3 + H_2O`

(iii) `2AlP + 3H_2SO_4 -> Al_2(SO_4)_3 + PH_3 uparrow`

`text(Physical Properties :)`

(i) It is having 'rotten fish' smell.

(ii) It is soluble in `CS_2` and insoluble in water.

(`NH_3` is soluble in water)

`NH_4^(+) +OH^(-)`

`overset(..)(PH_3) +H_2O -> PH_4^(+) OH^(-)`

(lone pain on `P` is in `s`-orbital , so donating capicity is less)

`PH_4^(+)` is formed with acids

(iii) Like `NH_3`, `PH_3` also can form addition product.

`CaCl_2*8NH_3` `Cu_2Cl_2*2PH_3`, `AlCl_3*2PH_3`, `SnCl_4*2PH_3`

`PH_3` can be absorbed by `Ca(OCl)Cl`.

`PH_3 + 3Ca(OCl)Cl + 3H_2O -> PCl_3 + 3HCl + 3Ca(OH)_2`

`2NH_3 + 3Ca(OCl)Cl -> N_2 + 3CaCl_2 + 3H_2O`

Other Reactions of `PH_3` :

(i) `PH_3 +O_2 -> P_2O_5 +H_2O`

(ii) `PH_3 + 3Cl_2 -> PCl_3 + 3HCl`

(iii) `PH_3 + 4N_2O undersettext(sparking)oversettext(electrical)-> H_3PO_4 +4N_2`

(iv) `underset[text(detection of)(2PH_3)] PH_3 + 3CuSO_4 -> undersettext(Black ppt.)(Cu_3P_2 downarrow) +3H_2SO_4`

(v) `PH_3 + 6AgNO_3 -> undersettext(yellow ppt)([Ag_3P * 3AgNO_3 downarrow]) + 3HNO_3`

`Ag_3P * 3AgNO_3 + 3H_2O -> undersettext(Black ppt)(6Ag downarrow) + 3HNO_3 + H_3PO_3`

(vi) `PH_3 + 4HCHO + HCl -> undersettext(white colourless solid which is used for making fire-proof cotton fabrics)([P(CH_2OH)_4]^(+)Cl^(-))`

`text(Example of dehydrating reaction of)` `P_2O_5` :

`HClO_3 + P_2O_5 -> 2HPO_3 + Cl_2O_7`

`H_2SO_4 + P_2O_5 -> 2HPO_3 + SO_3`

`HNO_3 + P_2O_5 -> 2HPO_3 + N_2O_5`