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?

Which of the following species does not have a tetrahedral shape?

1. \(\mathrm{NH}_{4}^{+}\)
2. \(\mathrm{SiCl}_{4}\)
3. \(\mathrm{SF}_{4}\)
4. \(\mathrm{SO}_{4}^{2-}\)

Which of the following are peroxoacids of sulphur?
1. \(\mathrm{H}_{2} \mathrm{SO}_{5} \text { and } \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{8}\)
2. \(\mathrm{H}_{2} \mathrm{SO}_{5} \text { and } \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{7}\)
3. \(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{7} \text { and } \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{8}\)
4. \(\mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{6} \text { and } \mathrm{H}_{2} \mathrm{~S}_{2} \mathrm{O}_{7}\)

In the preparation of compounds of Xe, Bartlett had taken \(O_{2}^{+}PtF_{6}^{-}\) as a base compound. This is because: 

1. Both ${\mathrm{O}}_2$ and Xe have same size.

2. Both ${\mathrm{O}}_2$ and Xe have same electron gain enthalpy.

3. Both ${\mathrm{O}}_2$ and Xe have almost same ionisation enthalpy.

4. Both Xe and ${\mathrm{O}}_2$ are gases.