Question

what is the pH of an aqueous solution at 25 degrees celcius that is 3.3 m HNO3

Answer 1

Answer – Given, molality of HNO₃ = 3.3 m

We know, molality means moles / kg of solvent

So, mass of solvent = 1 kg and we know density of water = 1.0 g/mL

So, volume of water = 1 kg = 1000 g = 1000 mL = 1 L

So, molarity of HNO₃ = 3.3 M

We know HNO₃ is strong acid

[HNO₃] = [H₃O⁺] = 3.3 M

So, pH = -log [H₃O⁺]

            = - log 3.3 M

             = -0.52