[plu]

If approximately 50:50 of benzoic acid (m.p. 122 °C) and 2-fluorobenzoic acid (m.p. 122 °C) are mixed, the observed melting point of the mixture will be
(a) sharp at 122 °C
(b) sharp but slightly above 122 °C
(c) sharp but slightly below 122 °C
(d) over a wide range but ending at 122 °C
(e) over a wide range and ending well below 122 °C

My best guess for this question would be (e) as I would expect the two compounds to interfere with the  intermolecular bonding of each other, thus lowering melting points.  However, I've never worked with mixtures of compounds with melting points so close so I really don't know what to make of this problem