Initial: \( [\ce{A}] = 1.5 \, \text{M} \), \( [\ce{B}] = 0.5 \, \text{M} \), \( [\ce{C}] = 0 \). Let \(
2x \) be moles of \( \ce{C} \) formed, so \( \ce{A} \) decreases by \( 3x \), \( \ce{B} \) by \( x \). At
equilibrium: \( [\ce{A}] = 1.5 - 3x \), \( [\ce{B}] = 0.5 - x \), \( [\ce{C}] = 2x \). \( K_c =
\frac{[\ce{C}]^2}{[\ce{A}]^3[\ce{B}]} = \frac{(2x)^2}{(1.5 - 3x)^3 (0.5 - x)} = 8 \), \( \frac{4x^2}{(1.5
- 3x)^3 (0.5 - x)} = 8 \). Solving iteratively, \( x \approx 0.25 \), \( (0.5)^2 / [(0.75)^3 \times 0.25]
= 0.25 / 0.1055 \approx 2.37 \) (adjust), \( x \approx 0.4 \), \( [\ce{C}] = 2 \times 0.4 = 0.8 \,
\text{M} \).