Which of the following contains salts of H₃PO₃?

I. NaH₂PO₃    II. Na₂HPO₃    III. Na₃PO₃  

1. I, and II only

2. I, II, and III

3. II and III only

4. III only

Which of the following statements is false?

1. ONCl and ${\mathrm{ONO}}^{- }$are isoelectronic.

2. ${\mathrm{O}}_3$ molecule is bent

3. Ozone is violet-black in solid-state

4. Ozone is diamagnetic gas

Element/s that form pπ - pπ multiple bonds with themselves, as well as with carbon and oxygen are:

1. P, As

2. N, As

3. N, P

4. N

A substance that gives a brick red flame and breaks down on heating to give oxygen and a brown gas is:

1. Calcium carbonate

2. Magnesium carbonate

3. Calcium nitrate

4. None of the above

Nitrogen gas is liberated by the thermal decomposition of:

1. ${\mathrm{NH}}_4{\mathrm{NO}}_2$                                 

2. ${\mathrm{NaN}}_3$

3. ${\left({\mathrm{NH}}_4\right)}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$                           

4. All of the above. 

Which of the following statements about the subsequent reactions is false?
\(XeF_6 + H_2O \text{(excess)} \longrightarrow\ 'X' + HF \)
\(XeF_6 + 2H_2O \longrightarrow\ 'Y' + HF \)

1. 'X' is explosive

2. 'Y' is an oxyacid of xenon

3. Both are example of non-redox reaction

4. ${\mathrm{XeF}}_6$ can undergo partial hydrolysis

Which of the following compound does not exist?

1. XeOF₄

2. NeF₂

3. XeF₂

4. XeF₆ 

Which of the following hydrides is the most acidic?

1. H₂Te

2. H₂Se

3. H₂O

4. H₂S

P forms multiple bonds in POCl₃ by using

1. $p\mathrm{\pi }-\mathrm{p\pi }$

2. $d\mathrm{\pi }-\mathrm{d\pi }$

3. $p\mathrm{\pi }-\mathrm{d\pi }$

4. None of the above.

Which of the following statements about phosphorus is false?
1. It is non-metal.
2. It exists as a tetrahedral molecular solid.
3. It is less reactive than nitrogen.
4. P-P bond is much weaker than $N\equiv N$ bond.