To find the hybridisation of nitrogen in different species, we use this rule:
| Number of regions | Hybridisation | Geometry |
|---|---|---|
| 2 | sp | Linear |
| 3 | sp2 | Trigonal planar |
| 4 | sp3 | Tetrahedral |
1) NO3− (Nitrate ion):
2) NO2 (Nitrogen dioxide):
3) NO2− (Nitrite ion):
4) NO2+ (Nitronium ion):
Conclusion: Only NO2+ has nitrogen in sp hybridisation.
Correct answer: (C) NO2+

From the given following (A to D) cyclic structures, those which will not react with Tollen's reagent are : 
Compound 'P' undergoes the following sequence of reactions : (i) NH₃ (ii) $\Delta$ $\rightarrow$ Q (i) KOH, Br₂ (ii) CHCl₃, KOH (alc), $\Delta$ $\rightarrow$ NC-CH₃. 'P' is : 


Which of the following statement(s) is/are correct about the given compound?

Such a group of atoms is called a molecule. Obviously, there must be some force that holds these constituent atoms together in the molecules. The attractive force which holds various constituents (atoms, ions, etc.) together in different chemical species is called a chemical bond.
There are 4 types of chemical bonds which are formed by atoms or molecules to yield compounds.