Question:medium

Which from following compounds is least soluble in water at STP?

Show Hint

Hydrocarbons are non-polar and hydrophobic (water-fearing).
Updated On: May 15, 2026
  • $\text{C}_2\text{H}_5\text{OH}$
  • $\text{CH}_3\text{OH}$
  • $\text{CH}_3\text{NH}_2$
  • $\text{CH}_4$
Show Solution

The Correct Option is D

Solution and Explanation

Step 1: Understanding the Concept:
Solubility in water depends on "like dissolves like" and the ability to form hydrogen bonds.
Step 2: Key Formula or Approach:
Polar molecules with $-\text{OH}$ or $-\text{NH}_2$ form hydrogen bonds with water and are soluble. Non-polar molecules are insoluble.
Step 3: Detailed Explanation:
- (A) Ethanol ($\text{C}_2\text{H}_5\text{OH}$) and (B) Methanol ($\text{CH}_3\text{OH}$) form strong H-bonds and are miscible with water.
- (C) Methylamine ($\text{CH}_3\text{NH}_2$) also forms H-bonds.
- (D) Methane ($\text{CH}_4$) is a non-polar hydrocarbon with no ability to form H-bonds. It is practically insoluble in water.
Step 4: Final Answer:
$\text{CH}_4$ is the least soluble compound.
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