71.

The basicity of H₃PO₄ is

• 2

• 3

• 4

• 5

NH₃ has much higher boiling point than PH₃ because

• NH₃ has larger molecular weight

• NH₃  undergoes umbrella inversion

• NH₃ forms hydrogen bond

• NH₃ contains ionic bonds whereas PH₃ contains covalent bonds.

Iodine readily dissolves in potassium iodide solution giving

• I^-

• KI^-

• KI^-₂

• KI₃

Which among the following is paramagnetic ?

• Cl₂O

• ClO₂

• Cl₂O₇

• Cl₂O₆

Acetic acid reacts with PCl₅, to form

• CH₂ClCOOH

• CHCl₂COOH

• CH₃COCl

• CH₃COOCl

Sulphur does not exist as S₂ molecule because

• it is less electronegative

• it is not able to constitute $\mathrm{p\pi }-\mathrm{p\pi }$ bonds

• it has ability to exhibit catenation

• of tendency to show variable oxidation states

Polyanion formation is maximum in

• nitrogen

• sulphur

• oxygen

• boron

Oleum is

• castor oil

• oil of vitriol

• fuming H₂SO₄

• none of the above

Oxidation number of sulphur in Caro's acid is 

• +6

• +4

• +8

• +7

Liquor ammonia is

• ammonium hydroxide

• liquified ammonia gas

• concentrated solution of NH₃ in water

• a solution of NH₃ in alcohol