Question 5 of 50intermediate🔧 ApplyNumerical3 marks

Calculate (a) molality (b) molarity and (c) mole fraction of KI if the density of 20% (mass/mass) aqueous KI is 1.202 g mL-1.

(a)
Answer

Molality = 1.5 mol kg⁻¹

(b)
Answer

Molarity = 1.45 mol L⁻¹

(c)
Answer

Mole fraction of KI = 0.0263

Explanation

This problem requires understanding of concentration terms. For a 20% (mass/mass) solution, we assume 20 g KI in 100 g solution, giving 80 g water as solvent. Molality is temperature-independent (moles of solute per kg solvent), while molarity depends on temperature (moles per litre solution). Mole fraction is the ratio of moles of one component to total moles.

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