Among the following statements which is INCORRECT : (1) In the preparation of compounds of \(X e\), Bartlett had taken \(\mathrm{O}_{2} \mathrm{PtF}_{6}\) as a base compound because both \(\mathrm{O}_{2}\) and Xe have almost same ionisation enthalpy. (2) Nitrogen does not show allotropy. (3) A brown ring is formed in the ring test for \(\mathrm{NO}_{3}^{-}\)ion. It is due to the formation of \(\left[\mathrm{Fe}\left(\mathrm{H}_{2} \mathrm{O}\right)_{5}(\mathrm{NO})\right]^{2 *}\) (4) On heating with concentrated \(\mathrm{NaOH}\) solution in an inert atmosphere of \(\mathrm{CO}_{2}\), red phosphorus gives \(\mathrm{PH}_{3}\) gas.

Ionization enthalpy is the energy required to remove an electron from an atom or ion in its gaseous state. It plays a crucial role in understanding chemical reactivity and the formation of compounds. Higher ionization enthalpy means an atom holds onto its electrons more tightly, making it less likely to form positive ions.
In the context of xenon (Xe) and oxygen (O2), the similarity in their ionization enthalpies allowed chemist Neil Bartlett to hypothesize that xenon could form stable compounds much like oxygen does. He used \(\text{{O}}_2 \text{{PtF}}_6\) to demonstrate this because both elements have closely matched ionization energies. This groundbreaking discovery led to the synthesis of xenon compounds, changing the landscape of chemical bonding theories.

Allotropy refers to the existence of an element in more than one form, each having different physical or chemical properties. Nitrogen (N) exhibits allotropy primarily in the form of diatomic nitrogen (N2) and ionic nitrogen compounds. Diatomic nitrogen (N2) is the most common and stable form, making up about 78% of Earth's atmosphere.
Despite the claim in the exercise, nitrogen does show allotropy. Besides N2, nitrogen can exist in other forms under certain conditions. These allotropes are crucial for various chemical reactions and industrial processes.

The brown ring test is a classic analytical chemistry technique used to detect nitrate ions (NO3-) in a solution. When nitric acid (HNO3) and iron(II) sulfate (FeSO4) are combined, and concentrated sulfuric acid (H2SO4) is carefully added, a brown ring forms at the interface.
The brown ring is due to the formation of the complex ion \(\text{{[Fe(H}}_2\text{{O}})_5(\text{{NO}})]^{2+}\). This test is highly sensitive and provides a visual confirmation of the presence of nitrate ions. It’s a reliable method commonly used in chemistry laboratories.

Phosphorus, particularly red phosphorus, is known for its various chemical reactions. One notable reaction is when red phosphorus is heated with concentrated sodium hydroxide (NaOH) in an inert atmosphere of carbon dioxide (CO2). This reaction produces phosphine gas (PH3).
This gas is highly toxic and flammable. The reaction is written as:
\[ \text{4P + 3NaOH + 3H}_2\text{O} \rightarrow \text{PH}_3 + \text{3NaH}_2\text{PO}_2 \]
This reaction is significant in the study of phosphorus chemistry and is often used to demonstrate the properties and reactivity of phosphorus compounds in educational settings.