Read the following passage and find the two errors. Then, choose the answer that corrects the errors.

pH is a measure of the concentration of OH− ions in a solution of an acid or base. The pH scale plots the concentration of solutions in a range from 0–16.
pH is a measure of the concentration of H+ ions in a solution of an acid or base. The pH plots the concentration of solutions in a range from 0–14.
pH is a measure of the concentration of H+ ions in a solution of an acid or base. The basic scale plots the concentration of solutions in a range from 0–16.
pH is a measure of the concentration of OH− ions in a solution of water. The pH scale plots the concentration of solutions in a range from 0–12.
pH is a measure of the concentration of OH− ions in a solution of an acid or base. The acid scale plots the concentration of solutions in a range from 0–16.

the positions which points up in upward carbon and down in downward carbon are axial

and vice versa holds true for equatorial positions

so the correct answer with labelled diagram will be

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.