Question

The salt formed on reaction of copper oxide with hydrochloric acid is:
A.) Cuprous chloride
B.) Cupric chloride
C.) Both formed in 1:2 ratio
D.) Both formed in 1:3 ratio

Answer 1

Hint: Here you should assume it is copper(II) oxide or cupric oxide. It is the inorganic compound with the formula CuO. Now try to recall the reaction when it is reacted with hydrochloric acid.

Complete step by step answer:

Here we can see the reaction of copper oxide with hydrochloric acid -

$CuO(s)\quad +\quad 2HCl(aq)\quad \rightarrow\quad CuCl_{ 2 }(aq)\quad +\quad 2H_{ 2 }O(l)$

In this reaction, one mole of CuO reacts with two moles of hydrochloric acid to produce one mole of cupric chloride and two moles of the water molecule. You can see that the salt formed in this reaction is $CuCl_{ 2 }$ (cupric chloride).

Therefore, we can conclude that the correct answer to this question is option B.

Additional information:
Copper(II) oxide is the starting point for the production of other copper salts.
For example, many wood preservatives are produced from copper oxide.
Cupric oxide is used as a pigment in ceramics to produce blue, red, and green, and sometimes grey, pink, or black glazes.
It is also used when welding with copper alloys.

Note: Copper(I) oxide or cuprous oxide is the inorganic compound with the formula $Cu_{ 2 }O$. It dissolves in hydrochloric acid to give solutions of $CuCl_{ 2 }^{ - }$.
We should know that in aqueous solution $Cu^{ 2+ }$ ion exists as $[Cu(H_{ 2 }O)_{ 6 }]^{ 2+ }$, which has a quite beautiful blue color.