20) Which substance is an acid?

A)
Ba(OH)2

B)
CH3COOCH3

C)
H3PO4

D)
NaCl

can someone help

H3PO4

Explanation:

The H3PO4 is an acid as it release H+ ion when dissolved in a solution and H3PO4 is known as phosphoric acid

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.