Online learning requires students and teachers to communicate interactively by utilizing information and communication technology, such as computer media with the internet, mobile phones with various applications, video, telephone or fax. Online learning is very suitable to be applied to the outbreak of Coronavirus Disease 2019 . This study aims to determine the difficulties of students in online learning the subject of hydrocarbons. This research is a descriptive study with the instruments used in the form of 15 item questions and a questionnaire of 20 items. From the results of the study, students had abilities with high criteria of 7.92%, students had medium criteria abilities of 3.33%, students had abilities of low criteria 88.75%. Students have difficulty in answering the problem of determining the primary, secondary, tertiary C atom; IUPAC nomenclature of alkanes, alkenes, alkyne, and reactions to hydrocarbons. Face-to-face learning cannot be replaced with online learning because students are not used to independent learning, insufficient facilities, insufficient internet quota. Online learning on the subject of hydrocarbons is not enough to use an android cellphone, but requires a laptop, computer or notebook. Training on the use of Chemsketch or Chemdraw is required in describing the structure and nomenclature of IUPAC. A safe and conducive environment, harmonious parental and family assistance is indispensable in online learning. Student interest and motivation are very much needed in independent learning to be the key to the success of online learning.