Please say which is the anode (oxidation) and which is the cathode (reduction) 2H+ + 2e- ➖> H2 (g)

2I- ➖> I2 + 2e-

Explanation:

1st one will be cathodic reaction and reduction will occur since electrons are being gained and hydrogen goes from +1 to zero oxidation state.

2nd one will be anodix reaction and oxidation will take place because Iodide ion's oxidation number increases from -1 to 0

where is the following

explanation:

hydrocarbons are organic compounds that contain only hydrogens and carbons. they can be saturated (those which contain only carbon-carbon single bonds) or unsaturated (those which contain carbon-carbon double or triple bonds) in nature. hydrocarbons can undergo several reactions like substitution, elimination etc.  

on substituting one or more hydrogen atoms in hydrocarbon it results in the formation of haloalkane. as the halogen atoms are large compared to the carbon and hydrogen atoms, due to which the molecular weight increases and the bond become polar because of presence electronegative halogen atom and results in the increase in boiling point of the haloalkane.

thus, the correct option is (b) that is the boiling point of the new compound increases on substituting a hydrogen atom with a halogen in a hydrocarbon.