When copper turnings and concentrated $HCl$ are heated with copper sulphate,the compound formed is:

In the dichromate dianion $(Cr_2O_7^{2-})$,which of the following statements is correct regarding the $Cr-O$ bonds?

$Cu^{2+}$ aqueous solution has . . . . . . colour.

Potassium manganate $(K_2MnO_4)$ is not formed in which of the following reactions?

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:

Among $Co^{3+}$,$Ti^{2+}$,$V^{2+}$ and $Cr^{2+}$ ions,one if used as a reagent cannot liberate $H_{2}$ from dilute mineral acid solution,its spin-only magnetic moment in gaseous state is $.....$ $B.M.$ (Nearest integer)