Problem 21 - 43 Years JEE ADVANCED (1978-2020) + JEE MAIN Chapterwise & Topicwise Solved Papers Chemistry

Question

The hybridisation of atomic orbitals of nitrogen in \(\mathrm{NO}_{2}^{+}, \mathrm{NO}_{3}^{-}\)and \(\mathrm{NH}_{4}^{+}\)are (a) \(s p, s p^{3}\) and \(s p^{2}\) respectively (b) \(s p, s p^{2}\) and \(s p^{3}\) respectively (c) \(s p^{2}, s p\) and \(s p^{3}\) respectively (d) \(s p^{2}, s p^{3}\) and \(s p\) respectively

Step-by-Step Solution

Answer

Option (b): \(sp, sp^2, sp^3\) respectively.

Step 1: Determine Hybridization of NO2+

The nitrogen in \(\mathrm{NO}_{2}^{+}\) forms two bonds with oxygen and has no lone pairs. The generic formula is \(AX_2\), which correlates to linear geometry. For such linear configurations, the hybridization is \(sp\). Thus, nitrogen in \(\mathrm{NO}_{2}^{+}\) is \(sp\) hybridized.

Step 2: Determine Hybridization of NO3-

In \(\mathrm{NO}_{3}^{-}\), nitrogen is bonded to three oxygen atoms. The molecular ion has a trigonal planar geometry, represented by the formula \(AX_3\), with zero lone electron pairs. This geometry implies \(sp^2\) hybridization for nitrogen. Thus, nitrogen in \(\mathrm{NO}_{3}^{-}\) is \(sp^2\) hybridized.

Step 3: Determine Hybridization of NH4+

In \(\mathrm{NH}_{4}^{+}\), nitrogen forms four equivalent \(N-H\) bonds. The structure is tetrahedral, given by the generic formula \(AX_4\). Tetrahedral geometry is associated with \(sp^3\) hybridization. Thus, nitrogen in \(\mathrm{NH}_{4}^{+}\) is \(sp^3\) hybridized.

Step 4: Match Results with Given Options

Based on the step-by-step hybridization analysis: \(\mathrm{NO}_{2}^{+}\) is \(sp\), \(\mathrm{NO}_{3}^{-}\) is \(sp^2\), and \(\mathrm{NH}_{4}^{+}\) is \(sp^3\). This sequence matches option (b): \(sp, sp^2, sp^3\).

Key Concepts

Molecular Geometry

Molecular geometry is the three-dimensional arrangement of atoms within a molecule. It helps us understand how molecules interact with each other and with various environments. The geometry of a molecule is determined by the number of bonds and lone pairs found around the central atom. For example:

• Linear geometry has all atoms in a straight line, formed by molecules such as \(\mathrm{NO}_2^+\), where nitrogen forms two bonds with two oxygen atoms and has no lone pairs, resulting in an \(sp\) hybridization.
• Trigonal planar geometry appears in \((\mathrm{NO}_3^-)\), where nitrogen is bonded to three oxygen atoms, giving the molecule a flat, triangular shape with \(sp^2\) hybridization.
• Tetrahedral geometry can be seen in molecules like \(\mathrm{NH}_4^+\), where the central nitrogen forms four single bonds with hydrogen, leading to \(sp^3\) hybridization.

Recognizing these geometries helps predict how molecules will behave chemically and physically in different environments.

Chemical Bonding

Chemical bonding is the process through which atoms combine to form molecules. These bonds can be covalent, ionic, or metallic, each with distinct properties and behaviors. For nitrogen compounds such as \(\mathrm{NO}_2^+\), \(\mathrm{NO}_3^-\), and \(\mathrm{NH}_4^+\), we mainly focus on covalent bonds:

• In covalent bonding, atoms share electrons to fill their outermost electron shells and attain stability. Nitrogen, which has five valence electrons, often forms multiple covalent bonds to reach a full outer shell of eight electrons.
• The type of bond influences the compound's properties, such as its boiling and melting points, solubility, and conductivity.
• Nitrogen's ability to form triple and double bonds, such as in nitrogen dioxide and nitrate ions, greatly affects molecular stability and reactivity.

Understanding chemical bonding is crucial for predicting how different compounds will react with one another.

Nitrogen Compounds

Nitrogen compounds encompass a vast range of substances where nitrogen is bonded to different elements. These compounds play critical roles in both natural and industrial processes. Let's look at some key aspects:

• In organic chemistry, nitrogen is often part of functional groups like amines, amides, and nitriles. These structures are pivotal in pharmaceuticals, agriculture, and polymers.
• Inorganic nitrogen compounds, like those in \(\mathrm{NO}_2^+\) and \(\mathrm{NO}_3^-\), are involved in various environmental processes, including the nitrogen cycle, which is essential for life on Earth.
• Nitrogen's versatility in bonding enables the creation of stable, diverse structures, leading to wide-ranging applications, from fertilizers to explosives.

By studying nitrogen compounds, we can manipulate and utilize chemical reactions for beneficial purposes in many different fields of science and industry.