Can someone help me out in this chemistry question

When svante arrhenius first proposed his acid-base theory, he was a doctoral candidate. his professors thought his ideas were unfounded. within a decade, the arrhenius theory of acid-base was widely accepted and praised within the scientific world. arrhenius defined acids as compounds having ionizable hydrogen and bases as compounds with ionizable a) barium. b) hydronium. c) hydroxide. d) oxygen.

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation:

What is the main reason why some developing countries fear the increase the free trade policies around the world?