28. If the total pressure of a mixture of four gases (neon, carbon dioxide, oxygen and hydrogen) is 1245 mm Hg, what is the pressure of neon gas if the pressure of carbon dioxide is 145 mm Hg, the pressure of hydrogen is
499 mm Hg and the pressure of oxygen is 228 mm Hg?

Partial pressure of Neon is 373 mmHg

Explanation:

In a mixture of gases, the total pressure is equal to the sum of the partial pressures of each gas. In the problem:

Total Pressure = Partial Pressure Ne + Partial Pressure CO2 + Partial pressure O2 + Partial pressure H2

Replacing:

1245 mmHg = Partial pressure Ne + 145mmHg + 228mmHg + 499mmHg

Partial pressure Ne = 1245 - 145 - 228 - 499

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.