Redox Reactions...

When a piece of sodium metal is dropped in water, hydrogen gas evolved because:

Arrange the following in increasing order of oxidation state of $$Ni$$.
$$K_2[Ni(CN)_4],K_2[NiF_6],Ni(CO)_4$$

Oxidation number of iodine in $${ IO }_{ 3 }^{ - }, { IO }_{ 4 }^{ - }, KI$$ and $$I_2$$ respectively is _____

In the conversion of $$Br_2\ to\ Br{ O }_{ 3 }^{ - }$$, the oxidation state of $$Br$$ changes from:

What will be the reduction potential for the following half-cell reaction at $$298$$K?
(Given: $$[Ag^+]=0.1$$M and $$E^o_{cell}=+0.80$$V)

Which of the following is a redox reaction?

Which of the following is the cell reaction that occurs when the following half-cells are combined?
$$I_2+2e^-\rightarrow 2I^-(1M)$$; $$E^o=+0.54$$V
$$Br_2+2e^-\rightarrow 2Br^-(1M); E^o=+1.09$$V

$$E^o$$ values for the half cell reactions are given:
$$Cu^{2+}+e^-\rightarrow Cu^+$$; $$E^o=0.15$$V
$$Cu^{2+}+2e^-\rightarrow Cu$$; $$E^o=0.34$$V
What will be the $$E^o$$ of the half-cell: $$Cu^{+}+e^-\rightarrow Cu$$?

In the redox reaction ,
$$Pb_3O_4 + 8HCl \rightarrow 3PbCl_2 + Cl_2 + 4H_2O$$ :

Which of the following is not an example of redox reaction ?