Question

Which of the following best describe the particles present in a 2.0 M aqueous solution of Al(NO3)3?

2 M Al3+(aq) and 18 M NO3-(aq)
2 M Al(NO3)3(aq)
2 M Al3+(aq) and 6 M NO3-(aq)
2 M Al3+(aq) and 3 M NO3-(aq)

Answer 1

2 M Al³⁺(aq) and 6 M NO₃⁻(aq)

Step-by-step explanation:

Al(NO₃)₃ is a strong electrolyte that ionizes according to the following equation.

Al(NO₃)₃(aq) → Al³⁺(aq) + 3 NO₃⁻(aq)

The solution 2.0 M contains 2.0 moles of Al(NO₃)₃ per liter of solution.

The molar ratio of Al(NO₃)₃ to Al³⁺ is 1:1. The concentration of Al³⁺ is:

2.0 mol Al(NO₃)₃/L × (1 mol Al³⁺/1 mol Al(NO₃)₃) = 2.0 mol Al³⁺/L = 2.0 M Al³⁺

The molar ratio of Al(NO₃)₃ to NO₃⁻ is 1:3. The concentration of NO₃⁻ is:

2.0 mol Al(NO₃)₃/L × (3 mol NO₃⁻/1 mol Al(NO₃)₃) = 6.0 mol NO₃⁻/L = 6.0 M NO₃⁻