Question

. What is the mole fraction of commercial "concentrated" hydrofluoric acid, which is 55.0 % HF by mass?​

Answer 1

Answer:

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Answer 2

we have to find the mole fraction of commercial concentrated hydrochloric acid which is 55 % HF by mass.

solution : let mass of solution is 100g , then mass of HF would be 55g.

now mass of HF = 55g

molecular mass of HF = 20g/mol

so, no of moles of HF = 55/20 = 2.75 mol

mass of water = 100g - 55g = 45g

molecular mass of water = 18g/mol

so no of moles of water = 45/18 = 2.5 mol

so mole fraction of hydrofluoric acid = 2.75/(2.5 + 2.75) = 2.75/5.25 = 0.524

Therefore mole fraction of hydrofluoric acid is 0.524