The orange-red color of an aqueous solution of $K_2Cr_2O_7$ changes to lemon yellow when treated with aqueous $KOH$. What is the reason for this?

Which of the following is most basic in nature?

$CrO_3$ is a/an ...

Which of the following substances will not give the borax bead test?

Identify correct statements from below:
$A$. The chromate ion is square planar.
$B$. Dichromates are generally prepared from chromates.
$C$. The green manganate ion is diamagnetic.
$D$. Dark green coloured $K_2MnO_4$ disproportionates in a neutral or acidic medium to give permanganate.
$E$. With increasing oxidation number of transition metal,ionic character of the oxides decreases.
Choose the correct answer from the options given below:

Write a note on halide compounds of transition elements.