What should the molar concentrations of benzoic acid and sodium benzoate be in a solution that is buffered at a pH of 4.55 and has a freezing point of -2.0 °C? (Assume complete dissociation of sodium benzoate and a density of 1.01 g/mL for the solution.)

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everyone so asked that the concentration of Hydrofluoric acid In studying floor ride in a breakfast solution with a ph of 3.57. It has a freezing point of negative 5.5°C. In the density of 1.02 g per meal leader. You know the Hydrofluoric acid is H. F. sodium fluoride is N. A. F. So the first thing we're gonna do is use the Henderson has back equation to find the ratio of the concentrations. And this is P. H. Eagle's peak A plus the law of the consulate base by weak acid and R. P. K. A. It's 3.14. They're gonna have 3.57. He gets 3.14. That's the law of the consulate based the bye bye week accent. You get 0.43 give us a law, other kinds of base by by weak acid. So for the race yet We get 2.69. So now we need to calculate the morality is in the freezing point depression equation is the change in the freezing point equal to them allow freezing point constant kinds of morality in moles per kilogram. Soon after you rearrange this is all for m gonna get em because delta T. F. About by K. F. We get negative 5.5 Grace Celsius By -1.86 C divided by M. And we get 2.96. Cloudy. So now we're going to assume that we have one kg of the solvent and we can find the most. Using the morality equation. We know that Malachi. It was the moles of the solute. About about a kilogram of the solvent. They're gonna have malls because the melody James, kelly graham And we get 2. morality one kg, Would you give us 2.96 walls Hydrofluoric acid. This is one particle. We're setting fluoride. This can disassociate 22 particles. We have 2.96 malls, Those malls of Hydrofluoric acid Plus two malls of sodium Floren. So another equation we can use is the ratio of the conjugate base about about a weak acid Equal to 2.69. And then malls studying fluoride about moles of hydrogen fluoride, how do you feel like asking? And this is 2.69. So now, if we combine both equations and solve for it, we're gonna have 2.96 malls equal some balls of Hydrofluoric acid. Last two malls, I'm sending fluoride. You have malls, I'm sending floor. And what about malls patrick acid? And we get 2.69. Tonight we have malls Of sodium fluoride to 2.69. How smalls of Hydrofluoric acid. We get 2. Malls. It was a mold of Hydrofluoric acid plus two. That was 2.69 malls of Hydrofluoric acid 2. moles. It was the malls of Hydrofluoric acid Plus 5.38 malls of Hydrofluoric acid, Then we get 2.96 malls equal to 6.38 malls of Hydrofluoric acid. Some malls of Hydrofluoric acid Is 0. malls. The nine malls upsetting fluoride. It was 2.69. That was 0.46 malls Get 1.24 Malls Annapolis in one kg. We can use the density to calculate the volume of one kg. You have 1000 g and one kg In 1 m1.02 g, which is the density. Then we have one leader has 1000 ml. We get 0.98 L. Can I can calculate the polarity similarity of Hydrofluoric acid, 0.46 moles five by 0.98 leaders get 0. and clarity is 1. moles By 0.98 Leaders get 1.27 polarity

What should the molar concentrations of benzoic acid and sodium benzoate be in a solution that is buffered at a pH of 4.55 and has a freezing point of -2.0 °C? (Assume complete dissociation of sodium benzoate and a density of 1.01 g/mL for the solution.)

Verified Solution

Key Concepts

Buffer Solutions

Henderson-Hasselbalch Equation

Freezing Point Depression