For a cell, $$\mathrm{Cu}(\mathrm{s})\left|\mathrm{Cu}^{2+}(0.001 \,\mathrm{M}) \| \mathrm{Ag}^{+}(0.01 \,\mathrm{M})\right| \mathrm{Ag}(\mathrm{s})$$

the cell potential is found to be $$0.43 \mathrm{~V}$$ at $$298 \mathrm{~K}$$. The magnitude of standard electrode potential for $$\mathrm{Cu}^{2+} / \mathrm{Cu}$$ is _________ $$\times 10^{-2} \mathrm{~V}$$.

[Given : $$E_{A{g^ + }/Ag}^\Theta $$ = 0.80 V and $${{2.303RT} \over F}$$ = 0.06 V]

Assuming $$1 \,\mu \mathrm{g}$$ of trace radioactive element X with a half life of 30 years is absorbed by a growing tree. The amount of X remaining in the tree after 100 years is ______ $$\times\, 10^{-1} \mu \mathrm{g}$$.

[Given : ln 10 = 2.303; log 2 = 0.30]

Sum of oxidation state (magnitude) and coordination number of cobalt in $$\mathrm{Na}\left[\mathrm{Co}(\mathrm{bpy}) \mathrm{Cl}_{4}\right]$$ is _________.

Consider the following sulphur based oxoacids.

$$\mathrm{H}_{2} \mathrm{SO}_{3}, \mathrm{H}_{2} \mathrm{SO}_{4}, \mathrm{H}_{2} \mathrm{S}_{2} \mathrm{O}_{8}$$ and $$\mathrm{H}_{2}\mathrm{S}_{2} \mathrm{O}_{7}$$.

Amongst these oxoacids, the number of those with peroxo $$(\mathrm{O}-\mathrm{O})$$ bond is ________.