Among the following, the coloured compound is :

Both [Ni(CO)$$_4$$] and [Ni(CN)$$_4$$]$$^{2-}$$ are diamagnetic. They hybridisations of nickel in these complexes, respectively, are :

The IUPAC name of [Ni(NH$$_3$$)$$_4$$] [NiCl$$_4$$] is :

Electrolysis of dilute aqueous NaCl solution was carried out by passing 10 milli ampere current. The time required to liberate 0.01 mol of H$$_2$$ gas at the cathode is (1 Faraday = 96500 C mol$$^{-1}$$].