–(d) Brass ornaments tarnish after a time because the
copper in them is gradually oxidized to copper(II) oxide.
•(i)
Complete the symbol equation for this reaction.
• 2Cu +
…… ®
2CuO [1]
•(ii) Brass ornaments which have been tarnished can be
cleaned with a dilute solution of hydrochloric acid. The
copper(II) oxide reacts with the hydrochloric acid. Complete the
word equation for this reaction.
•
–Copper(II)
oxide + hydrochloric acid ®
[2]
•
•(iii)
Explain why copper(II) oxide is behaving as a basic oxide in this reaction.
[1]