Hydrogenation straightens fat chains for tighter packing

Steps:

• Unsaturated fats have double bonds creating kinks in hydrocarbon chains.
• Hydrogenation adds hydrogen atoms, breaking double bonds to form saturated fats.
• Saturated chains become straight and flexible.
• Straight chains pack more closely, raising melting point.

Why A is correct:

• Saturated fats lack double bonds, allowing linear hydrocarbon chains to align and pack tightly via van der Waals forces, unlike kinked unsaturated chains.

Why the others are wrong:

• B: Fats remain nonpolar and insoluble in water regardless of saturation.
• C: Hydrogenation eliminates double bonds, reducing their number.
• D: Saturated fats solidify at room temperature, unlike liquid unsaturated fats.

Final answer: A