Identify the basic oxide from the following:

Assertion $(A)$: $CuI_2$ cannot be prepared by the reaction of $Cu^{2+}_{(aq)}$ with $I^{-}_{(aq)}$.
Reason $(R)$: Aqueous $Cu^{2+}$ solution is blue in colour.
The correct answer is:

Which is a stronger reducing agent,$Cr^{2+}$ or $Fe^{2+}$,and why?

Which of the following metals becomes passive when treated with concentrated $HNO_3$?

At $pH = 12$,what change occurs in $Cr_2O_7^{2-}$?

All $Cu(II)$ halides are known except $CuI_2$,because ....