There is no sodium found in nature in pure form due to its reactivity. What does this say about activation energy of the reaction of sodium and water compared to the combustion of wax in a candle?

The activation energy of a chemical reaction is the energy that is required to be supplied for a chemical reaction to take place. The activation energy for the reaction of sodium is low compared to the energy released such that the reaction of sodium and water is spontaneous resulting in the melting of the sodium into liquid form

The activation energy of a candle wax is much higher, requiring the ignition of the wick which burns and in turn melts the candle wax to release vapors that burns alongside the wick to produce sooth carbon dioxide, carbon monoxide and water vapor and release of heat energy which also fuels further combustion of the candle wax and wick

Therefore, the activation energy of the candle wax and wick which require the heat of direct flame from an ignited matches is higher than the activation energy of sodium placed in a medium of water that reacts spontaneously without heat application

Explanation:

the answer is c. nacl

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.