Question

What is the pH of a water sample having \( H^+ \) concentration of 10 mg/L? The atomic weight of H is 1 g/mol.

• A. 2
• B. 4
• C. 6
• D. 8

Hint:

The pH of a solution can be calculated by taking the negative logarithm of the concentration of hydrogen ions in moles per liter.

Answer 1

The Correct Option is A

The pH of a solution is calculated using the formula: \[ \text{pH} = -\log[H^+]. \] Given that the concentration of \( H^+ \) is 10 mg/L and the atomic weight of hydrogen is 1 g/mol, we can convert the concentration into moles per liter: \[ \text{Concentration of } H^+ = \frac{10 \, \text{mg/L}}{1 \, \text{g/mol}} = 10^{-2} \, \text{mol/L}. \] Now, applying the formula for pH: \[ \text{pH} = -\log(10^{-2}) = 2. \] Final Answer: \[ \boxed{2}. \]