Naphtalene has the lowest melting point instead of benzoic acid, cinnamic acid and acetanilide. Why?

Question

Naphtalene's structure composed of two benzene ring. Does it affect its melting point?

Thanx for all

Answer 1

The intermolecular forces holding naphthalene together are weaker than the others. Only van der Waals forces attract molecules of naphthalene to each other, while the other three can use hydrogen bonding as well as being polar to bind molecules together (benzoic acid being C6H5COOH, cinnamic being trans-C6H5CH=CHCOOH, and acetanilide being C6H5NHC{=O]}CH3).

Answer 2

you may desire to establish an ICE chart (I = preliminary, C = substitute, E = equilibrium) for a vulnerable acid. HB = cinnamic acid on the right of the chart, you will have HB --> H+ + B- The preliminary quantity of HB is a million.6*10^-3 The substitute for HB is -x, on a similar time as the substitute for H+ and B- is +x The equilibrium quantity for HB is a million.6*10^-3 - x The equilibrium quantity for H+ is x. Ka = [H+]^2/[HB] So Ka = x^2/(a million.6*10^-3 - x) because of the fact x is any such small sort, that's removed from the denominator without inflicting lots disturbance. so which you're left with Ka = x^2/a million.6*10^-3 After plugging in Ka and fixing for x, you get: x = 2.40 3*10^-4 = [H+] -log ([H+]) = pH pH = 3.sixty one