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Here is today’s DAT Question of the Day from Dr. Jim Romano.
Cobalt(II) chloride hexahydrate is a red-pink, crystalline, water-soluble solid often used as a humidity indicator, in electroplating, and as a catalyst in organic synthesis.
At infinite dilution, what is the Van’t Hoff factor value?
A) 1
B) 2
C) 3
D) 7
E) 8
F) 9
Take a moment and decide before scrolling.
Correct Answer: C) 3
When cobalt(II) chloride hexahydrate dissolves:
CoCl2·6H2O → Co2+ + 2 Cl−
Number of particles formed in solution:
1 Co2+
2 Cl−
Total particles = 3
Van’t Hoff factor (i) = 3
Classic DAT Trap.
Do NOT count the 6 waters of hydration.
They are part of the crystal lattice and become solvent water — not independent solute particles.
This is why D, E, and F are wrong.
Strong DAT performance requires understanding dissociation and colligative properties conceptually — not memorizing patterns.
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2026 Math Destroyer – DAT and OAT Quantitative Reasoning Prep
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