The correct increasing order for the acid strength of nitrogen oxides is: 

1. ${\mathrm{N}}_2\mathrm{O }< \mathrm{NO }< {\mathrm{N}}_2{\mathrm{O}}_{\mathrm{4 }}< {\mathrm{N}}_2{\mathrm{O}}_{\mathrm{3 }}< {\mathrm{N}}_2{\mathrm{O}}_5$

2. ${\mathrm{N}}_2\mathrm{O}$ $< \mathrm{NO }< {\mathrm{N}}_2{\mathrm{O}}_{\mathrm{3 }}< {\mathrm{N}}_2{\mathrm{O}}_{\mathrm{4 }}< {\mathrm{N}}_2{\mathrm{O}}_5$

3. ${\mathrm{N}}_2\mathrm{O}$ $< {\mathrm{N}}_2{\mathrm{O}}_{\mathrm{3 }}< {\mathrm{N}}_2{\mathrm{O}}_{\mathrm{4 }}< {\mathrm{N}}_2{\mathrm{O}}_{\mathrm{5 }}< \mathrm{NO}$

4. $\mathrm{NO }< {\mathrm{N}}_2\mathrm{O}$ $< {\mathrm{N}}_2{\mathrm{O}}_{\mathrm{3 }}< {\mathrm{N}}_2{\mathrm{O}}_{\mathrm{4 }}< {\mathrm{N}}_2{\mathrm{O}}_5$

In the compounds of the type POX₃, the P atom multiple bond is of the type

(1) $p\mathrm{\pi }-\mathrm{p\pi }$

(2) $d\mathrm{\pi }-\mathrm{d\pi }$

(3) $p\mathrm{\pi }-\mathrm{d\pi }$

(4) None of these

Which of the following statement is not true for phosphorus?

Dipole moment is highest for

(1) NCl₃

(2) NBr₃

(3) NI₃

(4) NF₃

The basicity of the acids H₃PO₂, H₃PO₃, H₃PO₄  and H₄P₂O₇ are respectively

(A) 1,2,3,7

(B) 2,3,4,7

(C) 1,2,3,4

(D) 1,2,3,5

The correct order of decreasing Lewis acid strength of trichlorides of group 15 elements is

$\left(A\right) AsC{l}_3>PC{l}_3>BiC{l}_3>SbC{l}_3$
$\left(B\right)PC{l}_3>AsC{l}_3>SbC{l}_3>BiC{l}_3$
$\left(C\right) NC{l}_3>PC{l}_3>AsC{l}_3>SbC{l}_3$
$\left(D\right)SbC{l}_3>BiC{l}_3>PC{l}_3>AsC{l}_3$

Which of the following flourides has the least capacity as fluoride ion acceptor

(1)AsF₅

(2) SbF₅

(3) PF₅

(4) None of these

The ionic character of H-X is highest in

(1) HBr

(2) HI

(3) HF

(4)HCl

The strongest acid is

(1) H₃PO₂ 

(2) H₃PO₃ 

(3) H₄P₂O₇ 

(4) H₃PO₄ 

Which of the following HY(hydra-acid of halogen) is the strongest acid, best reducing agent, is the least stable and is easily oxidised

(1) HF

(2) HCl

(3) HBr

(4) HI