False. carbon-carbon bonds that share 2 pairs of electrons are double bonds. An unsaturated hydrocarbon isnt necessary to only have double bonds. they can also have single bonds or triple bonds.
An unsaturated hydrocarbon is a chain of carbon and hydrogen atoms in which adjacent carbon atoms are attached together through double or triple bond.
Since it is known that carbon atom forms covalent compounds so, an unsaturated hydrocarbon not only contains double or triple bonds it also has single bonds in between.
Thus, we can conclude that the statement all of the covalent carbon-carbon bonds in unsaturated hydrocarbons share 2 pairs of electrons, is false.
The crushed tablets would stop bubbling/fuzzing first because it has a smaller surface area which means that it would dissolve before the uncrushed tablets which has a larger surface area.