The student is now told that the four solids, in no particular order, are barium chloride (BaCl2BaCl2), sugar (C6H12O6C6H12O6), butanoic acid (C3H7COOHC3H7COOH), and potassium bromide (KBrKBr). Assuming that conductivity is correlated to the number of ions in solution, rank the four substances based on how well a 0.20 MM solution in water will conduct electricity.

Explanation:

Conductivity is proportional to number of ions .

Bacl₂ ionises as follows

BaCl₂ ⇄ Ba⁺² + 2Cl⁻¹

No of ions after ionisation = 3 .

Bacl₂ is a strong electrolyte so it will ionise to the maximum extent .

KBr ⇄ K⁺ + Br⁻

It is also a strong electrolyte but no of ions present after ionosation = 2

so its conductivity will be less than Ba Cl₂.

C₃H₇COOHC₃H₇COOH) ⇄C₃H₇COO⁻C₃H₇COO⁻ + 2H⁺

here no of ions after ionisation is 3 but the degree of ionisation of organic acid is very less or organic acid  ionises very less . So it will conduct to some extent .

Sugar is a non ionising organic molecule . So it will be almost non ionising and non conducting .

Hence the order in which they can be arranged from highest to least conducting is as follows

BaCl₂ > KBr > C₃H₇COOHC₃H₇COOH  > sugar .