How many $EDTA$ (ethylenediaminetetraacetic acid) molecules are required to make an octahedral complex with a $Ca^{2+}$ ion?

Which of the following is the formula of tartar emetic?

The bonds in $K_4[Fe(CN)_6]$ are:

Which of the following statements is true about $[Cu(NH_3)_4]SO_4$?

An excess of $AgNO_3$ is added to $100 \ mL$ of a $0.01 \ M$ solution of dichlorotetraaqua-chromium$(III)$ chloride. The number of moles of $AgCl$ precipitated would be

The primary valency and secondary valency of the central metal ion and the number of total ions produced in an aqueous solution for the $K[Co(OX)_2(NH_3)_2]$ complex are,respectively, . . . . . . .