1. alginate is
a. reversible hydrocolloid impression material
b. irreversible hydrocolloid impression material
c. polysulfideimpression material
d. polyvinyl siloxane impression material

Option b, Irreversible hydrocolloid impression material

Explanation:

Irreversible is used as an impression material to take impression from edentulous jaws. It is also used in wound healing and drug delivery.

Alginate is a natural polymer found in cell wall of brown seaweed.

Its monomers are β-D-mannuronate and α-L-guluronate.

In association with Ca2+, it forms gel. It is hydrophilic in nature.

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.