5 0 2
This question is about salts and electrolysis.
Do not write
outside the
box
A student wants to make copper chloride crystals.
The student adds excess copper oxide to some hot acid.
The student stirs the mixture.
0 2 . 1
Which acid should the student use?
[1 mark]
Tick (✓) one box
Hydrochloric acid
Nitric acid
Sulfuric acid

Explanation:

In order to produce CuCl2 crystals, there have to be copper and chlorine atoms.

Copper oxide (CuO) has copper atoms. We need the acid to have chlorine atoms.

Out of HCl, HNO3 and H2SO4, only HCl has chlorine atoms.

CuO + 2HCl => CuCl2 + H2O.

Hence the answer is Hydrochloric acid.

Balance the following equations. Enter 1 as a coefficient for reactants and products which have no coefficient.

(NH4)2Cr2O7(s) _> Cr2O3(s)+N2(g)+H2O(g)

Explanation: