Name the complex ion [al(cn)6]3−. the oxidation number of aluminum is +3.

Hexacyanoaluminate III

Explanation:

A complex ion consists of a central metal ion and ligands. The number of ligands present is known as the coordination number of the complex ion. Complex ions could be positive or negative.

The ion in the question is a negative complex ion. Negative complex ions have their names ending with -ate. The number of ligands is first mentioned, followed by the name of the ligand(s) and lastly the central metal is named ending in -ate followed by its oxidation number in the complex ion.

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.