Which of the following statements is not valid for oxoacids of phosphorus? 

• Orthophosphoric acid is used in the manufacture of triple superphosphate

• Hypophosphorous acid is a diprotic acid

• All oxoacids contain tetrahedral four coordinated phosphorus

• All oxoacids contain tetrahedral four coordinated phosphorus

Which one of the following molecules contains no pi -bond?

• CO₂

• H₂O

• SO₂

• SO₂

Strong reducing behaviour of H₃PO₄ is due to

• the presence of one -OH group and two P-H bonds

• high electron gain enthalpy of phosphorous 

• the high oxidation state of phosphorus

• the high oxidation state of phosphorus

In Which of the following arrangement, the given sequence is not strictly according to the property indicated against it ? 

• HF < HCl< HBr < HI : increasing acidic strength

• H₂O < H₂S < H₂Se < H₂Te : increasing pK_a values.

• NH₃ < PH₃ < AsH₃ < SbH₃  : increasing acidic character

• NH₃ < PH₃ < AsH₃ < SbH₃  : increasing acidic character

Oxidation states of P in H₄P₂O_5, H₄P₂O₆, H₄P₂O₇, are respectively

• +3, +5, +4

• +5, +3, +4

• +5, +4,+3

• +5, +4,+3

XeF₂ is isostructural with 

• TeF₂

• ICl^-₂

• SbCl₃

• SbCl₃

Which of the following is a polar molecule?

• BF₃

• SF₄

• SiF₄

• SiF₄

The stability of +1 oxidation state among Al, Ga, In and TI increases in the sequence

• Ga<In< Al<Tl

• Al<Ga<In<Tl

• Tl<In<Ga<Al

• Tl<In<Ga<Al

The variation of the boiling point of the hydrogen halides in the order HF >  HI > HBr > HCl. What explains the higher boiling point of hydrogen fluoride?

• The electronegativity of fluorine is much higher than for other elements in the group

• There is strong hydrogen bonding between HF molecules

• The bond energy of HF molecules is greater than in other hydrogens halides

• The bond energy of HF molecules is greater than in other hydrogens halides

Which of the following oxide is amphoteric?

• SnO₂

• CaO₂

• SiO₂

• SiO₂