Question

What is the molar concentration of hydrogen ions in a solution of $ 0.1 \, \text{M} $ $ \text{HCl} $?

• A. \( 0.1 \, \text{M} \)
• B. \( 0.05 \, \text{M} \)
• C. \( 0.2 \, \text{M} \)
• D. \( 1 \, \text{M} \)

Hint:

Remember: Strong acids like \( \text{HCl} \) dissociate completely, so the concentration of hydrogen ions is equal to the concentration of the acid.

Answer 1

The Correct Option is A

Step 1: Understand the dissociation of \( \text{HCl} \)
Hydrochloric acid (\( \text{HCl} \)) is a strong acid and dissociates completely in water: \[ \text{HCl} \rightarrow \text{H}^+ + \text{Cl}^- \]
Step 2: Determine the concentration of \( \text{H}^+ \)
Due to complete dissociation of \( \text{HCl} \), the \( \text{H}^+ \) ion concentration equals the \( \text{HCl} \) concentration. 
Given: \( \text{HCl} \) concentration = \( 0.1 \, \text{M} \). 
Therefore, the \( \text{H}^+ \) ion concentration is \( 0.1 \, \text{M} \). 
Answer:
The molar concentration of hydrogen ions is \( 0.1 \, \text{M} \). Option (1) is correct.