Final answer:
Cocaine hydrochloride is the form of cocaine that is typically injected because it is water-soluble, contrasting with crack cocaine, which is a free-base version more suitable for smoking.
Step-by-step explanation:
The form of cocaine that is typically injected is cocaine hydrochloride. This form is soluble in water, making it easy to be absorbed into the bloodstream when injected. It is also the form that is commonly snorted, as it is readily absorbed through the mucous membranes of the nose.
On the other hand, crack cocaine is a free-base and more volatile version of cocaine that is often smoked because it vaporizes at a lower temperature and thus cannot be easily dissolved in water for injection. When smoked crack cocaine allows for rapid absorption of the substance into the bloodstream via the lungs reaching the brain in about 15 seconds and providing an intense high.