If equal masses of each substance absorb the same amount of heat, which substance undergoes the greatest temperature change

If equal masses of each substance absorb the same amount of heat, the substance which undergoes the greatest temperature change is: the one with the lowest specific heat capacity.

Specific heat capacity can be defined as the quantity of heat required to raise the temperature of a physical object or body per unit mass, by one degree Celsius (1°C) or one Kelvin (1 K).

This ultimately implies that, specific heat capacity is the quantity of heat absorbed or released per unit mass of a substance when its temperature increases by one degree Celsius (1°C) or one Kelvin (1 K).

Mathematically, the quantity of heat is given by the formula;

Where:

Making the subject of formula, we have:

Deductively, a substance undergoes the greatest temperature change when its specific heat capacity is lowest and its mass remains constant.

Read more: link

See explanation

Explanation:

The heat capacity of a substance is determined by the chemical composition of the substance and its mass.

Now, if substances have equal masses, the substance with the lesser heat capacity undergoes the greater temperature change.

Hence, among the substances, the particular one with the lowest heat capacity is expected to undergo the greatest temperature change.

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.