The catalyst that is used in the contact process is:

1.	Fe2O3	2.	Al2O3
3.	V2O5	4.	SO3

The chemical formula of oleum is - 

The correct order of bond dissociation energy of halogens ${\text{F}}_2, {\mathrm{Cl}}_2, {\mathrm{Br}}_2 \mathrm{and} {\mathrm{I}}_2$ is-

1. F₂ < Cl₂ < Br₂ < I₂

2. I₂ > Br₂ > F₂ > Cl₂

3. Cl₂ > Br₂ < F₂ > I₂

4. I₂ < F₂ < Br₂ < Cl₂

The correct increasing order of basic strength of hydrides:

1. BiH₃ \(\simeq \) SbH₃ < AsH₃ < PH₃ < NH₃ 
2.  BiH₃  > NH₃  > PH₃ > SbH₃ > AsH₃ 
3. SbH₃ < AsH₃ < PH₃ < NH₃ < BiH₃ 
4. AsH₃ > NH₃ > PH₃ > SbH₃ > BiH₃

Lead nitrate upon heating gives:

1. N₂O, PbO 
2. NO₂, PbO 
3. NO, PbO 
4. NO, PbO₂

An element that does not show allotropy is:
1. Nitrogen
2. Phosphorus
3. Antimony
4. Arsenic

The maximum covalency of nitrogen is:

1. 3

2. 5

3. 4

4. 6

Which of the following statements is false? 

A brown ring formed in the ring test for ${\mathrm{NO}}_3^{-}$ ion is due to the formation of:
1. [Fe(H₂O)₅(NO)]²⁺
2. FeSO₄.NO₂
3. [Fe(H₂O)₄(NO)₂]²⁺
4. FeSO₄.HNO₃

Bismuth is present in a +5 oxidation state in: 

1. \(\mathrm{Bi}_{2} \mathrm{O}_{5}\)
2. \(\mathrm{BiF}_{5}\)
3. \(\mathrm{BiCl}_{5}\)
4. \(\mathrm{Bi}_{2} \mathrm{~S}_{5}\)