Chrome yellow is chemically known as

The alloy that contains copper and $Zn$ is $x$ and the one that contains copper and $Ni$ is $y$. What are $x$ and $y$ respectively?

The ionic charges on chromate ion and dichromate ion respectively are:

Iodine is formed when potassium iodide reacts with a solution of

Fill in the blanks:
$(1)$ Since $V_2O_5$ acts as both an acid and a base,it is an ...... oxide.
$(2)$ The $Cr$ oxide which is basic is ......,and the $Cr$ oxide which is amphoteric is ...... .
$(3)$ The formula of chromite ore is .......... .
$(4)$ The formula of sodium dichromate crystal is .......... .

Consider the following reactions:
$K_2Cr_2O_7$ $\xrightarrow[-H_2O]{KOH} [A]$ $\xrightarrow[-H_2O]{H_2SO_4} [B] + K_2SO_4$
The products $[A]$ and $[B]$,respectively,are: