Which of the following unsaturated hydrocarbons contains a triple bond?

Appeared in: RRB Nsg Superintendent -29 April 2025 (Shift-1st)

Explanation

Ethyne is the correct answer as it belongs to the alkyne family of hydrocarbons.
The suffix '-yne' in the name 'Ethyne' specifically indicates the presence of a carbon-carbon triple bond (C≡C).
Alkynes are classified as unsaturated hydrocarbons because their carbon atoms do not hold the maximum possible number of hydrogen atoms due to the triple bond.

Option A: Ethane is an alkane, which is a saturated hydrocarbon. Its structure contains only a carbon-carbon single bond.
Option C: Methane is the simplest alkane and a saturated hydrocarbon. It contains only single bonds between carbon and hydrogen.
Option D: Propene is an alkene, which is an unsaturated hydrocarbon, but it contains a carbon-carbon double bond, not a triple bond.

Visual 1: Diagram: Comparison of the molecular structures of Ethane (single bond), Propene (double bond), and Ethyne (triple bond), highlighting the bond types.
Visual 2: Flowchart: Classification of hydrocarbons into saturated (alkanes) and unsaturated (alkenes, alkynes) categories with examples.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Classification of hydrocarbons and identification of alkynes based on bond type as background academic context rather than a clinical decision trigger.
Understanding basic organic chemistry, including hydrocarbon structure, is a fundamental prerequisite for grasping the structure and function of complex biomolecules (like lipids and proteins) and the mechanism of action of drugs in pharmacology.
Certain hydrocarbon derivatives are used clinically as general anesthetics (e.g., halothane, sevoflurane). Their chemical structure and bonding determine their potency, solubility, and side effects.
What if the question asked for a hydrocarbon with a double bond? In that case, the correct answer would be Propene, as the '-ene' suffix signifies a double bond.

How to Approach the Question

First, identify the key terms in the question: 'unsaturated hydrocarbon' and 'triple bond'.
Recall the definitions. 'Unsaturated' means the molecule contains at least one double or triple bond. 'Triple bond' is the specific feature to look for.
Analyze the nomenclature of the options. The suffix of the name indicates the type of carbon-carbon bonds present.
The suffix '-ane' (as in Ethane, Methane) indicates an alkane with single bonds.
The suffix '-ene' (as in Propene) indicates an alkene with a double bond.
The suffix '-yne' (as in Ethyne) indicates an alkyne with a triple bond.

Concept Tested & Keywords

Concept Tested: Classification of hydrocarbons and identification of alkynes based on bond type.
Stem keywords: unsaturated hydrocarbons, triple bond
Lead-in keywords: Which
Negative lead-in flag: false

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Practise the full RRB Nsg Superintendent -29 April 2025 (Shift-1st)

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