(1) Rosmarinic acid is hydrolyzed under acidic conditions to form A and B. A can undergo elimination reaction under the action of concentrated sulfuric acid to form organic matter C. Then B is, A is, and A undergoes elimination reaction to form C is, A contains -OH and -COOH, and their names are hydroxyl and carboxyl. The molecular formulas of A and C are the same, only the position of -COOH is different, and they are isomers of each other.

So The answer is: hydroxyl group, carboxyl group; b;

(2) Phenol -OH, -COOH, -COOC- all react with NaOH, then 1 mol of rosmarinic acid can completely react with an aqueous solution containing 6 mol mol NaOH at most, Therefore, the answer is: 6;

(3) B can react with H2O to form D under certain conditions, that is, an addition reaction occurs between B and water, and the same C is connected to -OH and -COOH,

The benzene ring in D can add to hydrogen, -COOH can react with sodium bicarbonate to generate gas, -OH can esterify with acetic acid, and -COOH can esterify with ethanol. ,

So the answer is: abcd;

(4) B→D is an addition reaction, and the reaction is,

So the answer is:; addition Reaction;

(5) B contains C=C, and addition polymerization reaction can occur, and the resulting polymer E is,

So the answer is:.