Question

A solution with a pH of 10 has a hydronium ion concentration of?

1) 10⁻¹⁰ mol/L
2) 10¹⁰ mol/L
3) 10 mol/L
4) -10 mol/L

Answer 1

A solution with a pH of 10 has a hydronium ion concentration of 10⁻¹⁰ mol/L.

The correct answer is option 1:
`\(10^(-10) \, \text{mol/L}\).`

Step-by-step explanation:

The pH of a solution is a measure of its acidity or alkalinity and is defined as the negative logarithm (base 10) of the hydronium ion concentration H₃O⁺. The pH scale ranges from 0 to 14, where lower pH values indicate acidic solutions, higher pH values indicate basic (alkaline) solutions, and a pH of 7 is considered neutral.

The relationship between pH and hydronium ion concentration is given by the equation:

`\[ \text{pH} = -\log[H_3O^+] \]`

For a solution with a pH of 10, we substitute the pH value into the equation:

`\[ 10 = -\log[H_3O^+] \]`

To find the hydronium ion concentration H₃O⁺, we take the inverse logarithm (antilog) of -10:

`\[ [H_3O^+] = 10^(-10) \]`

Therefore, the correct answer is option 1:
`\(10^(-10) \, \text{mol/L}\).`