Question

Cu > CuO > CuCl2 > Cu(OH)2 > CuO

Answer 1

2Сu + O2 -> 2CuO
CuO + 2HCl -> CuCl2 + H2O
CuCl2 + 2NaOH -> Cu(OH)2↓ + 2NaCl
Cu(OH)2 -> CuO + H2O

Answer 2

The given sequence represents the increasing order of the oxidation state of copper in the corresponding compounds.

• Copper (Cu) has an oxidation state of 0 since it is an uncombined element.
• In CuO, copper has an oxidation state of +2, which means it has lost two electrons.
• In CuCl2, copper has an oxidation state of +2 as well, because chlorine is more electronegative than copper and has taken both electrons from copper.
• In Cu(OH)2, copper has an oxidation state of +2, similar to CuO and CuCl2, as hydroxide ions are not strong enough to extract electrons from copper.
• CuO is repeated in the sequence, so it doesn't add any new information.

So, the sequence is:

Cu < CuO (+2) < CuCl2 (+2) < Cu(OH)2 (+2)