Question

Urea \(\mathrm{NH}_{2}-\mathrm{C}-\mathrm{NH}_{2}\) is obtained during formation of ammonium cyanate by using \(\mathrm{KCNO}\) and \(\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}\) $$ \mathrm{NH}_{2} \mathrm{CONH}_{2} \rightleftharpoons \mathrm{NH}_{4} \mathrm{CNO} $$ Formation of urea suggests (A) Organic compound can never be synthesized in laboratory (B) Phenomenon of isomerism (C) Organic compound can be synthesized in laboratory (D) Both (B) and (C)

Short answer

The correct answer is (D) Both (B) and (C), as the formation of urea suggests the phenomenon of isomerism and that organic compounds can be synthesized in the laboratory.

Step-by-step solution

Understanding the given reaction

In the given reaction, urea NH2-C-NH2 is formed from ammonium cyanate (NH4CNO). The equation looks like this: \(NH_2CONH_2 \rightleftharpoons NH_4CNO\)

Analyzing the given statements

We will analyze each statement one by one. (A) Organic compound can never be synthesized in laboratory: This statement can be ruled out as the given reaction itself is a synthesis of urea, an organic compound, from inorganic reactants. (B) Phenomenon of isomerism: Isomerism is the phenomenon by which two or more compounds have the same molecular formula but different structural formulas. In this case, ammonium cyanate (NH4CNO) and urea (NH2-C-NH2) have the same molecular formula CH4N2O, but different structures. Thus, this statement is relevant. (C) Organic compound can be synthesized in laboratory: As mentioned in Step 1, urea is formed from ammonium cyanate, which shows that an organic compound can be synthesized in the laboratory. This statement is also relevant. (D) Both (B) and (C) – As discussed above, both statement (B) and statement (C) are relevant in this context.

Selecting the correct answer

Based on the analysis, both the phenomenon of isomerism (statement B) and organic compounds can be synthesized in the laboratory (statement C) are true in this context, so the correct answer is: \(D\)Both (B) and (C).

Key concepts

Urea Synthesis

Urea synthesis in the laboratory is a classic example of the ingenuity of organic chemistry. Urea, with the chemical formula \(NH_2CONH_2\), is an organic compound composed of carbon, nitrogen, oxygen, and hydrogen. Obtaining urea from inorganic compounds was first achieved by Friedrich Wöhler in 1828, debunking the theory that organic compounds could only be produced by living organisms.

The laboratory synthesis of urea involves the reaction between potassium cyanate (\(KCNO\)) and ammonium sulfate (\(\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}\)). This demonstrates that organic compounds can indeed be synthesized in the laboratory using simple inorganic reactants, paving the way for modern organic synthesis.

Isomerism

Isomerism is a core concept in organic chemistry that involves molecules with the same molecular formula but different arrangements of atoms, resulting in different properties. There are several types of isomerism, such as structural isomerism, stereoisomerism, and conformational isomerism. Structural isomers, also known as constitutional isomers, differ in the connectivity of their atoms or functional groups.

With urea and ammonium cyanate, we see a clear case of structural isomerism. While both compounds have the formula \(CH_4N_2O\), their atoms are connected differently. Urea has a carbonyl group attached to two amino groups, whereas in ammonium cyanate, the nitrogen is part of an ionic structure with ammonium and cyanate ions. This difference in bonding leads to dramatically different properties, despite their identical molecular formulas.

Laboratory Synthesis of Organic Compounds

The laboratory synthesis of organic compounds is an essential aspect of chemistry that allows the creation of a vast array of substances, ranging from those found within living organisms, to entirely new molecules with beneficial properties. The synthesis involves various chemical reactions and techniques, such as distillation, crystallization, chromatography, and spectroscopy for analysis.

The synthesis of urea in the laboratory marks a milestone in chemistry as it showed that organic compounds could be made from inorganic materials, laying the foundation of organic chemistry and demolishing the vitalism theory of the time, which held that organic compounds could only arise from living beings.

Ammonium Cyanate Conversion

Ammonium cyanate conversion into urea is not only a fascinating reaction due to its historical significance but also a brilliant illustration of isomerization, where one molecule is transformed into another with the same atoms but a different arrangement. This process entails a rearrangement reaction in which ammonium cyanate, initially formed from potassium cyanate and ammonium sulfate, isomerizes to become urea.

This conversion is key to understanding that chemical reactions can lead to different substances without a change in the molecular formula. This specific conversion also aids in comprehending the versatility of nitrogen compounds, demonstrating how they can interconvert, which has implications in both laboratory syntheses and potentially in biological systems.