Question

Which is not stable under ambient condition?

Answer 1

Copper (I) compounds are unstable in aqueous solution and undergo disproportio-nation. 

2Cu+ ---> Cu2+ + Cu 

The greater stability of Cu2+(aq) than Cu+(aq) is due to much more -ve Δhyd H of Cu2+(aq) than Cu+(aq) which is more than compensates for the second ionisation enthalpy of Cu.

Answer 2

under ambient condition, we feel nice.