Question

the molecular structures of linoleic acid and palmitic acid, two naturally occurring substances, are shown in the figure. based on the molecular structures shown in the figure, which molecule is likely to be solid at room temperature? a linoleic acid, because the absence of carbon - carbon double bonds allows the molecules to pack closely together. b linoleic acid, because the presence of carbon - carbon double bonds prevents the molecules from packing closely together. c palmitic acid, because the absence of carbon - carbon double bonds allows the molecules to pack closely together. d palmitic acid, because the presence of carbon - carbon double bonds prevents the molecules from packing closely together.

Explanation:

To determine which molecule is solid at room temperature, we analyze molecular packing. Saturated fatty acids (no double bonds) can pack closely, while unsaturated ones (with double bonds, causing kinks) cannot. Palmitic acid has no carbon - carbon double bonds (saturated), so its molecules pack closely, leading to higher melting points (solid at room temp). Linoleic acid has double bonds (unsaturated), so its molecules can't pack closely (liquid at room temp). Option A says linoleic acid (unsaturated) packs closely - wrong. Option B says linoleic acid (with double bonds) packs closely - wrong (double bonds prevent close packing). Option C says palmitic acid (saturated, no double bonds) allows close packing - correct. Option D says palmitic acid (saturated) has double bonds preventing packing - wrong (palmitic acid has no double bonds).

Answer:

C. Palmitic acid, because the absence of carbon - carbon double bonds allows the molecules to pack closely together.