[Sis290025]

State if each is true or false.

1 An impurity always lowers the melting point of an organic compound.

2 A sharp melting point for a crystalline organic sustance always indicates a pure single compound.

3 If the addition of a sample of compound A lowers the melting point of compound X, X and A cannot be identical.

I think that all are true, but I am unsure of 2.

Thanks.

[Mitch]

I doubt 2 is true. It seems absolute and nothing is absolute in organic chemistry.

[Yggdrasil]

(2) is false becaue eutectic mixtures can exhibit a sharp melting point despite being mixtures.

[youryanbing]

1.If there is some salt in it,it's mp may be high
2.I double it always true.I meet one time.It's mp is sharp,but HPLC purity is only 80%