Test: Phosphorus Halides & Oxoacids of Phosphorus - NEET MCQ

A translucent white waxy solid (A) reacts with excess of chlorine to give a yellowish white powder (B). Here B is PCl₅​.PCl₅​ reacts with organic compounds containing -OH group converting them into chloro derivative POCl₃​..PCl₅​ on hydrolysis gives (C).C is POCl₃​ and is finally POCl₃​ converted to phosphoric acid.

So  (A), (B) and (C) are P₄​,PCl₅​,POCl​₃.

Colour of PCl₅​ is not brownish but a greenish yellow crystalline solid with an irritating odour.

The axial bond pairs suffer more repulsion as compared to equatorial bond pairs.

Structure of PF₅

PF₅ has three axial bonds and two equitorial bonds and has sp₃d hybridisation PCl₅ has trigonal bipyramidal structure .

Due to this two Cl atoms lie along axial line and other three Cl atoms lie along the equatorial plane.

Hence Cl atoms which lie along axis have different bond length than that of Cl atoms lying on equatorial plane.

(A) Laughing Gas ⟶ Nitrous oxide.

As this gas sometimes generates a feeling of euphoria due to which a person wants to laugh after smelling it.

(B) Anhydride of HNO_3​ ⟶ anhydride means a compound obtained after water has been removed from other compounds.

From HNO₃​,H₂​O can't be removed  so, if we take 2(HNO_3​)

(C) Anhydride of HPO₃​

Similarly as above if we take

(D) Acid Anhydride of nitrogen.

Acid Anhydride is formed by the combination of two acid structures with an ion of a water molecule.

Hydrazine reacts with nitrous acid giving acid anhydride of nitrogen, i.e, hydrazoic acid with loss of 2 molecules of water.

N_2​H₄​ + HNO₂​ ⟶ HN₃​ + 2H₂​O

The number of P-O-P bond in cyclic metaphosphoric acid is three.

Pyrophosphoric acid (H₄P₂O₇) is tetrabasic acid.

H_3​PO_2​ ⟶ 3 + x − 4 = 0

x = +1

H₃​P₃​O₉​ ⟶  3 + 3x − 18 = 0

⇒ 3x = 15

⇒ x = +5

H₃​PO₄​ ⟶ 3  + x − 8 = 0

⇒ x = +5

H₃​PO₃​ ⟶ 3 + x − 6 = 0

⇒ x = +3

(A) H₃​PO_2​ ⟶ monobasic acid having 1 removable H⁺ ion.

(B) H_3​P_3​O₉​ ⟶ cyclic oxoacid

(Refer to Image)

(C) H₃​PO₄​⟶ Tribasic ⟶ having 3 removable H⁺ ion.

It is disproportional where Phosphorus changes from +3 to −3 and +5. So, this is an example of disproportion reaction.