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36 g of NaCl saturates 100 g water at 20°C. Express as mass % and check molarity approx. Step 1: Mass % = 36/(100+36) × 100 = 26.5% w/w. Step 2: Moles NaCl = 36/58.5 = 0.615 mol. Step 3: Solution volume ≈ 112 mL (density ~1.2) → M ≈ 0.615/0.112 ≈ 5.5 M. Step 4: Heating dissolves more (NaCl solubility rises slowly); cooling a hot saturated solution can give supersaturated — one crystal seed crashes it out.