An experiment is conducted in two steps. In step 1, a black solid compound is heated in a test
tube. The reaction produces a colourless gas that re-lights a glowing splint. Remaining in the
bottom of the test tube is a reddish-brown coloured solid metal. In step 2, the metal resulting
from step 1 is added to a tube of hydrochloric acid, and no reaction is observed.
a. Name the gas produced in step 1.
b. What type of reaction occurred in step 1? Provide a piece of evidence from the experiment
to support your answer.
Write the complete equation of the chemical reaction that occurred in step 1 only. Include
state symbols. Assume the cation in the reactants has the higher of its two possible charges.