Match the reaction on the right with the corresponding reaction on the left by writing the correct, matching number in the space provided.

solid sodium + chlorine gas → solid sodium chloride

solid sodium + liquid water → aqueous sodium hydroxide + hydrogen gas

2H2(g) + O2(g) → 2H2O(g)

2H2O2(aq) → O2(g) + 2H2O(l)

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.

metric time was an attempt to create a standard unit of time based off of 10, but it never took off an is not included in the metric system (si)