Which compound is known as inorganic benzene?

Appeared in: KPSC Staff Nurse - 2018

Explanation

Borazine is often called 'inorganic benzene' due to its remarkable structural and electronic similarities to benzene.
Its chemical formula is B₃N₃H₆, and it features a six-membered ring composed of alternating boron (B) and nitrogen (N) atoms.
Like benzene (C₆H₆), Borazine is a planar molecule and is isoelectronic (has the same number of valence electrons), which gives it some aromatic character.
However, the B-N bond is polar, making borazine more reactive than benzene.

Option A: Borax is a hydrated sodium borate salt (Na₂B₄O₇·10H₂O). It is a complex ionic compound, not a simple cyclic molecule like benzene.
Option B: Diborane (B₂H₆) is a simple boron hydride. It is a gas and has a non-cyclic structure with unique three-center, two-electron bonds.
Option D: Boric acid (H₃BO₃) is a weak acid. In its solid state, it forms a layered sheet-like structure held by hydrogen bonds, which is not analogous to the single-ring structure of benzene.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Chemical nomenclature and the concept of isoelectronic and isostructural compounds as background academic context rather than a clinical decision trigger.
While a pure chemistry concept, understanding structure-property relationships is fundamental in pharmacology. The shape and electronic nature of a molecule determine how it interacts with biological receptors.
The field of boron chemistry has significant medical applications. For example, bortezomib is a boron-containing compound used as a proteasome inhibitor in cancer therapy.
What if? If the question asked for an inorganic polymer with properties similar to polyethylene, the answer could involve polysiloxanes (silicones), demonstrating how replacing carbon with other elements creates new materials with unique properties.

How to Approach the Question

This is a factual recall question from inorganic chemistry.
First, identify the key term in the question: 'inorganic benzene'.
Recall the definition of benzene: a six-membered aromatic ring of carbon and hydrogen (C₆H₆).
The term 'inorganic' implies that carbon has been replaced by other elements. The term 'benzene' implies a similar ring structure and electron configuration (isoelectronic).
Evaluate the options: Borazine (B₃N₃H₆) has a six-membered ring of alternating Boron and Nitrogen atoms, making it the direct structural and electronic analogue to benzene.
Eliminate the other options as they are a salt (Borax), a simple hydride (Diborane), and an acid (Boric acid), none of which have the required cyclic structure.

Concept Tested & Keywords

Concept Tested: Chemical nomenclature and the concept of isoelectronic and isostructural compounds.
Stem keywords: compound, inorganic benzene
Lead-in keywords: Which

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Practise the full KPSC Staff Nurse - 2018

Attempt every question from this paper in a timed mock, then review the full solution for each one.