Which of the following represents the correct increasing order of basic strength of the Group 15 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

Which of the following elements does not exhibit allotropy?
1. Nitrogen
2. Phosphorus
3. Antimony
4. Arsenic

What is the maximum covalency exhibited by nitrogen?
1.Three (3)
2.Five (5)
3. Four (4)
4. Six (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

Which of the following compounds contains bismuth in the +5 oxidation state?
1. \(\mathrm{Bi}_{2} \mathrm{O}_{5}\)
2. \(\mathrm{BiF}_{5}\)
3. \(\mathrm{BiCl}_{5}\)
4. \(\mathrm{Bi}_{2} \mathrm{~S}_{5}\)

Which of the following correctly represents the gaseous products formed on heating ammonium dichromate and barium azide, respectively?

How many moles of nitric oxide (NO) are formed when 2 moles of ammonia (NH₃) undergo oxidation?

1. Two (2)

2. Three (3)

3. Four (4)

4. Six (6)

Which of the following represents the oxidation state of the central atom in the hypophosphite ion, H₂PO₂⁻, present in NaH₂PO₂?