Question

One classic chemistry experiment involves the reaction of hydrochloric acid and magnesium ribbon. A small piece of magnesium ribbon is placed in a test tube and hydrochloric acid is added to cover the magnesium. Students observe that the test tube gets hot, a gas (bubbles) is produced, and when a lit match is inserted in the mouth of the test tube, a loud "bark" is heard. This reaction is represented by the equation: Mg + 2HCl → MgCl2 + H2 The reaction can be described as both a _____________ reaction and a(n) ____________ reaction.
A) synthesis; endothermic
B) neutralization; exothermic
C) decomposition; neutralization
D) single replacement; exothermic

Answer 1

D, single replacement and exothermic. Single replacement because chlorine switches over to magnesium, exothermic because the reaction releases energy, evidenced by the test tube getting hot and the bark that's heard.