A solution containing 94.4 mL of carbon tetrachloride, CCl4, dissolved in 250.0 mL of nitrobenzene, C6H5NO2, was placed in the freezer, which dropped the temperature to 0°C. Did the solution freeze at that temperature? If so, at what temperature? The density of CCl4 is 1.59g/cm3. The density of C6H5NO2 is 1.2 g/cm3

the correct option is c.

isotopes refers to different forms of the same element with the same atomic number but different mass number as a result of difference in their neutron numbers. isotopes have different relative atomic mass but share the same chemical properties.

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.

i think it's letter a.