Classify each hydrogen atom in the following compounds as primary (1°), secondary (2°), or tertiary (3°).
c. 2-methylbutane
d. cyclohexane

Verified step by step guidance

1. Step 1: Understand the classification of hydrogen atoms. In organic chemistry, hydrogen atoms are classified based on the type of carbon atom they are attached to. A primary (1°) hydrogen is attached to a primary carbon, which is bonded to only one other carbon. A secondary (2°) hydrogen is attached to a secondary carbon, bonded to two other carbons. A tertiary (3°) hydrogen is attached to a tertiary carbon, bonded to three other carbons.
2. Step 2: Analyze the structure of 2-methylbutane. Draw the structure of 2-methylbutane, which is an alkane with a branched chain. The main chain is butane (four carbons), and there is a methyl group (CH₃) attached to the second carbon.
3. Step 3: Classify the hydrogen atoms in 2-methylbutane. Identify the types of carbon atoms in the structure. The first and last carbons in the chain are primary carbons, the second carbon is a tertiary carbon due to the methyl group, and the third carbon is a secondary carbon. Classify the hydrogen atoms based on these carbon types.
4. Step 4: Analyze the structure of cyclohexane. Cyclohexane is a cyclic alkane with six carbon atoms forming a ring. Each carbon in cyclohexane is bonded to two other carbons, making them secondary carbons.
5. Step 5: Classify the hydrogen atoms in cyclohexane. Since all the carbon atoms in cyclohexane are secondary, all the hydrogen atoms attached to these carbons are secondary (2°) hydrogens.

Key Concepts

Hydrogen Atom Classification

In organic chemistry, hydrogen atoms are classified based on the carbon atom they are attached to. A primary hydrogen is attached to a primary carbon, which is bonded to only one other carbon. A secondary hydrogen is attached to a secondary carbon, bonded to two other carbons, and a tertiary hydrogen is attached to a tertiary carbon, bonded to three other carbons.

Structure of 2-Methylbutane

2-Methylbutane is a branched alkane with the molecular formula C5H12. It consists of a butane backbone with a methyl group attached to the second carbon. Understanding its structure is crucial for identifying the types of hydrogen atoms present, as the branching affects the classification of the hydrogen atoms.

Structure of Cyclohexane

Cyclohexane is a cyclic alkane with the molecular formula C6H12, forming a six-membered ring. All carbon atoms in cyclohexane are equivalent, each bonded to two other carbons, making all hydrogen atoms secondary. Recognizing the ring structure helps in determining the uniform classification of hydrogen atoms in cyclohexane.