Problem 135 - A Complete Resource Book in Chemistry for JEE Main

Question

In analogy to \(\mathrm{O}_{2}^{+}\left[\mathrm{PtF}_{6}\right]\) a compound \(\mathrm{N}_{2}{\underline{\phantom{xx}}}^{+}\left[\mathrm{PtF}_{6}\right] \mathrm{Z}^{-}\) will not be formed because: (a) The ionization of \(\mathrm{N}_{2}\) gas is higher than that of \(\mathrm{N}\) atom (b) The ionization of \(\mathrm{N}_{2}\) gas is lower than that of \(\mathrm{O}_{2}\) gas (c) The ionization of \(\mathrm{N}_{2}^{-}\)gas is higher than that of \(\mathrm{O}_{2}\) gas (d) none of these

Step-by-Step Solution

Answer

The compound will not form because the ionization energy of _N_2 is higher than that of _O_2 (option b).

Step 1: Understanding the Context

In analogy to the formation of dioxygenyl hexafluoroplatinate, we are asked to evaluate if a similar compound can be formed with nitrogen. This involves understanding and comparing ionization energies which influence the formation of these ions.

Step 2: Identify Key Information

Identify that we need to compare ionization energies of nitrogen _N_2 molecules, as this is key to the formation of _N_2^+ ions needed to create the proposed compound with _[PtF_6]^-.

Step 3: Review Ionization Energies

Ionization energy for _N_2 is higher than that for _O_2. This generally results in _N_2 being more resistant to losing an electron to form _N_2^+ ions, compared to _O_2 to _O_2^+ ions.

Step 4: Assess Formation Feasibility

Given that _N_2 requires more energy to ionize than _O_2, forming the compound analogous to dioxygenyl hexafluoroplatinate is less feasible with nitrogen because creating _N_2^+ would require more energy than ionizing _O_2. Therefore, option (b) is considered.

Step 5: Conclusion

Since _N_2 has higher ionization energy than _O_2, the correct explanation for the lack of compound formation is option (b).

Key Concepts

Comparison of ionization energies

Ionization energy is an important concept in chemistry, as it tells us how much energy is required to remove an electron from an atom or a molecule. Different substances have different ionization energies, which can significantly impact chemical reactions and compound formations.
When comparing the ionization energies of nitrogen and oxygen, we need to remember that molecular substances like nitrogen, \(N_2\), and oxygen, \(O_2\), involve more complex interactions than single atoms.
In the case of \(N_2\) and \(O_2\), nitrogen has a higher ionization energy than oxygen. This means it requires more energy to remove an electron from \(N_2\) than from \(O_2\).

• For \(N_2\), the ionization energy is high due to the triple bond between the nitrogen atoms. This bond is very strong and stabilizes the molecule, making it less inclined to lose electrons.
• In contrast, \(O_2\) has a double bond and exhibits a lower ionization energy since these bonds don't hold the electrons as tightly as those in \(N_2\).

This difference plays a crucial role in determining how easily these molecules can form ions. Understanding these variances helps explain why \[N_2^+\] doesn't form compounds as easily as \[O_2^+\].

Nitrogen molecule ionization

Ionization of the nitrogen molecule, \(N_2\), is a process affected largely by its strong triple bond. The bond means that nitrogen atoms are heavily bonded, providing significant resistance to losing an electron.
When \(N_2\) attempts to form the ion \[N_2^+\], it must overcome this significant ionization energy barrier.

• The ionization energy for \(N_2\) is about 1402 kJ/mol, indicating the energy needed to create one positive ion per mole of nitrogen gas.
• This high energy requirement explains why \(N_2\) is typically very stable as a gas and does not easily give up electrons.

In simpler terms, \(N_2\) struggles to lose an electron due to its strong atomic bonds. This makes the creation of \[N_2^+\] quite challenging and less feasible in forming certain chemical compounds. This characteristic of \(N_2\) plays a big part in understanding why nitrogen compounds might not form as readily as those of other elements, like oxygen.

Compound formation feasibility

Compound formation involves the combination of different elements or ions to form a new substance. In this context, feasibility refers to how likely or easily a compound can be formed, based on the properties of the involved elements.
When considering the formation of a compound like \(N_2^+\)[PtF_6]^-, we must take into account the ionization energy of the nitrogen molecule.

• Given that \(N_2\) has a high ionization energy, it is not easily ionized to form \[N_2^+\].
• Oxygen, on the other hand, has a lower ionization energy, making it more feasible to lose an electron and form a compound like \(O_2^+\)[PtF_6]^-.

In this scenario, the high ionization energy of \(N_2\) effectively makes the formation of the analogous nitrogen compound less likely. More energy is needed to create the necessary ions, making such a reaction energetically unfavorable. Therefore, the ability to form new compounds like \(N_2^+\)[PtF_6]^- is limited by these energetic constraints, explaining why it doesn't occur as naturally as with oxygen.