When HNO2 is dissolved in water, it partially dissociates accordi...

Question

When HNO2 is dissolved in water, it partially dissociates according
to the equation HNO2ΔH+ + NO2- . A solution is prepared
that contains 7.050 g of HNO2 in 1.000 kg of water. Its
freezing point is -0.2929 °C. Calculate the fraction of HNO2
that has dissociated.

Accepted Answer

Hi everyone here we have a question telling us that Hydrofluoric acid only partially dissociates when dissolved in water. According to the equation Hydrofluoric acid forms hydrogen plus fluoride, a 76.58 g of Hydrofluoric acid was dissolved in 1500 g of water. To make a solution. The freezing of the solution is negative 4.9 to 6 degrees Celsius determine the fraction of Hydrofluoric acid dissociate. So we know that the change in our freezing temperature equals the freezing temperature of our solvent minus the freezing temperature of our solution. The change in freezing temperature equals R van hall factor times our freezing point constant, times our morality. Our freezing point constant equals 1. degrees Celsius per morality. The freezing point of our peer solvent Equals 0°C. The eye, actual or the fraction associated equals I actual minus one. So now we need to calculate our morality. So our molar mass of Hydrofluoric acid is .01 g per mole. Our moles of Hydrofluoric acid Is 76.5. 8 g times one mole over 20 .01g. and our g cancel out and that gives us 3.8271 moles of Hydrofluoric acid. Our massive water Equals 1500 g times one kg Over 10 to the 3rd g And our g cancel out, giving us 1.5 kg. So our morality Equals 3.827. 1 moles Divided by 1.5 kg equals 2. morality. Our change in temperature equals zero degrees Celsius minus negative 4.9 to 6 degrees Celsius Equals 4.9- and our I actual equals 4.926°C divided by 1.86°C per morality Times 2.5514 Morality Equals 1.03801. So our fraction dissociated Equals 1. 1 -1, which equals 0.03801. And that is our final answer. Thank you for watching. Bye.

When HNO2 is dissolved in water, it partially dissociates according to the equation HNO2ΔH+ + NO2- . A solution is prepared that contains 7.050 g of HNO2 in 1.000 kg of water. Its freezing point is -0.2929 °C. Calculate the fraction of HNO2 that has dissociated.

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