Help in identifying organic compound?

[Chap]

Question: The compound P has C,H,O and N as elements. A white pp+ was formed when P was acidified. Identify a structural feature of P which caused this precipitation.

 

I was thinking on the lines of: maybe its an ammonium salt of long chain carboxylic acid [e.g.- (CH)5COO-(NH4)+]. When a strong dilute acid is added, the carboxylic acid will be formed and since its a long chain molecule, it will precipitate out of the solution?

 

Am I right or is it some other obvious compound?

 

Thanks for answering.

Edited October 31, 2012 by Chap