Which of the following oxide is most acidic

(1) Na₂O

(2) Al₂O₃

(3) P₂O₅

(4) SO₃

The least acidic oxide among the following is:

1. P₄O₆ 

2. P₄O₁₀ 

3. As₄O₆ 

4. As₄O₁₀ 

Which of the following polyhalide ion is most stable

1. $B{r}_3^{-}$ 

2. $I_3^{-}$ 

3. $C{l}_3^{-}$ 

4. $F_3^{-}$ 

A diamagnetic element burns in air to form a dioxide.This dioxide can reduce iodine to HI. When H₂ gas is bubbled through this element, it forms a hydride.It was found that the reaction of the dioxide and hydride of this element produces the same metal again.The element is

(1) S

(2) Si

(3) Te

(4) PO

Point out the incorrect statement among the following :

(1) The oxidation state of oxygen is +2 in OF₂.

(2) Acidic character follows the order H₂O < H₂S < H₂Se < H₂Te.

(3) The tendency to form multiple bonds increases in moving down the group from sulphur to tellurium (towards C and N)

(4) Sulphur has a strong tendency to catenate while oxygen shows this tendency to a limited extent.

Which of the following statements is unacceptable?

(1) Among HClO₃, HClO₄,HClO and HClO₂, HClO₃ is the weakest acid.

(2)Bromide ion can be oxidised to Br₂ by chlorine.

(3) Cl₂O₇ is the anhydride of HClO₄.

(4) Among halide ions, F^- has the highest hydration energy.

Moist ammonia gas is dried over

(1) P₂O₅

(2) Anhydrous CaCl₂

(3)Quick lime

(4)Conc. H₂SO₄

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?