Throughout history, arsenic(III) oxide, known simply to the general public as "arsenic," has been a poison favored by murderers: It is tasteless, colorless, can be easily added to food or drink, produces symptoms that are similar to several diseases, and until the mid-1800s, was undetectable in the body. James Marsh developed the famous "Marsh test" for arsenic that was instrumental in convicting the murderer in a famous poisoning case in France in 1840. The Marsh test relies on the reaction of arsenic(III) oxide in a sample with elemental zinc and sulfuric acid to produce arsine (an analog of ammonia), zinc sulfate, and water. Upon igniting the final mixture, arsine is oxidized to elemental arsenic, and if captured on a ceramic bowl, a characteristic silvery-black powder would appear.
(a) Write the balanced chemical equations of the Marsh test.