Suppose you have an acid in your house with a ph of 1.2. this means you have a really strong acid in the house. how would you explain the term "strong acid" to someone who is not familiar with chemistry? how would you explain it to someone who is familiar with chemistry but just forgot what that term means?

Scientifically, there are various definitions for acid, but to the person who is not familiar with chemistry it can only be explained by experiment.

A simple experiment of acid and baking soda can be performed here. Suppose you have a solution in your house and you need to check if it is acidic or not, just add it to some amount of baking soda, if bubbles are formed, it confirms the solution is acidic. In this way, one can help a person to identify an acidic solution who is not familiar with chemistry.

To the person who is familiar with chemistry, it can be explained as a solution that turns blue litmus paper red and in the pH meter, the pH value lies between 0 to 7. If the value is close to zero, the acid is strong and it is weak if the value is close to 7. Here the pH of given  solution is 1.2 that means it is a strong acid.

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.

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.