Problem 12 - Chemistry and Chemical Reactivity

Question

Which of the following compounds can be a cyclo alkane? (a) \(\mathrm{C}_{3} \mathrm{H}_{5}\) (b) \(\mathrm{C}_{5} \mathrm{H}_{10}\) (c) \(\mathrm{C}_{14} \mathrm{H}_{30}\) (d) \(\mathrm{C}_{8} \mathrm{H}_{8}\)

Step-by-Step Solution

Answer

Compound (b) \(\mathrm{C}_5\mathrm{H}_{10}\) can be a cycloalkane.

Step 1: Identify Cycloalkane Formula

Cycloalkanes have a general formula of \(\mathrm{C}_n\mathrm{H}_{2n}\). This is because a cycloalkane is a closed ring structure with \(n\) carbon atoms and twice as many hydrogen atoms as carbon atoms. We will apply this formula to each of the given compounds to determine which can be a cycloalkane.

Step 2: Compare Compound (a)

The formula for compound (a) is \(\mathrm{C}_3\mathrm{H}_5\). To be a cycloalkane, it should follow the formula \(\mathrm{C}_3\mathrm{H}_6\). Since it has fewer hydrogen atoms, compound (a) does not fit the general cycloalkane formula.

Step 3: Compare Compound (b)

The formula for compound (b) is \(\mathrm{C}_5\mathrm{H}_{10}\). To be a cycloalkane, it should follow the formula \(\mathrm{C}_5\mathrm{H}_{10}\). This matches exactly, indicating that compound (b) could indeed be a cycloalkane.

Step 4: Compare Compound (c)

The formula for compound (c) is \(\mathrm{C}_{14}\mathrm{H}_{30}\). To be a cycloalkane, it should follow the formula \(\mathrm{C}_{14}\mathrm{H}_{28}\). Since it has more hydrogen atoms than required, compound (c) cannot be a cycloalkane.

Step 5: Compare Compound (d)

The formula for compound (d) is \(\mathrm{C}_8\mathrm{H}_8\). To be a cycloalkane, it should follow the formula \(\mathrm{C}_8\mathrm{H}_{16}\). Since it has fewer hydrogen atoms than required, compound (d) cannot be a cycloalkane.

Key Concepts

Organic Chemistry

Organic chemistry is all about the study of carbon-containing compounds. These compounds often include elements like hydrogen, oxygen, nitrogen, sulfur, and halogens. The unique ability of carbon to form long chains and rings allows for an immense variety of molecules, known as organic compounds.
Most of these organic compounds include hydrocarbons, which are fundamental frameworks that can be transformed into more complex structures. Hydrocarbons are the simplest organic molecules and serve as a foundation for studying various reactions and properties in organic chemistry. Understanding how different atoms connect in organic compounds is crucial for grasping the principles of organic chemistry.

Chemical Compounds

When we talk about chemical compounds, we are referring to substances formed by two or more elements chemically bonded together. In organic chemistry, the focus often falls on carbon-based compounds.
These compounds are classified based on their structures and types of bonds. They can have chains (alkanes, alkenes, alkynes), rings (cycloalkanes, aromatics), or complex geometries. Bonds in these compounds can be single, double, or triple, influencing the compound's properties and reactivity.

• Cycloalkanes: A special class of organic compounds with ring structures where all carbon atoms are connected by single bonds.
• Aromatics: Compounds with distinct rings and alternating double and single bonds showing resonance, like benzene.

Understanding these classifications helps us predict how compounds might behave or react under certain conditions.

Molecular Formula

A molecular formula is a compact way to express information about the atoms in a molecule. It denotes the number and type of each element found in a single molecule of the compound. For instance, \(\mathrm{C}_5\mathrm{H}_{10}\) tells us there are five carbon atoms and ten hydrogen atoms in the molecule.
Such formulas are crucial for determining what kind of chemical compound we are dealing with. In the context of cycloalkanes, the molecular formula is essential because it can directly indicate if the compound could form a ring structure.
Knowing the correct molecular formula helps chemists identify the class of the compound and guide further analysis.

Hydrocarbons

Hydrocarbons are the simplest organic compounds, consisting solely of carbon and hydrogen. They form the backbone of organic chemistry and include major classes such as alkanes, alkenes, alkynes, and cycloalkanes.
There are two main categories of hydrocarbons:

• Saturated hydrocarbons (e.g., alkanes): These have all single carbon-carbon bonds.
• Unsaturated hydrocarbons (e.g., alkenes, alkynes): These include one or more double or triple bonds, respectively.

Moreover, cycloalkanes belong to saturated hydrocarbons but form a closed ring.
Understanding hydrocarbons is fundamental to studying organic chemistry as they form the basic structures that can undergo various reactions to form more complex molecules.