$Cu_2Cl_2$ with $HCl$ in the presence of oxidizing agents gives:

Which of the following statements regarding copper salts is not true?

The blue borax bead is obtained by which of the following?

On heating a mixture of common salt and $K_{2}Cr_{2}O_{7}$ with concentrated $H_{2}SO_{4}$, a gas is evolved. The formula of the gas evolved and the oxidation state of the central metal atom in the gas, respectively, are:

The solution of $MnO_4^-$ is purple-coloured due to:

Pick out the incorrect statement: