Identify the statements that accurately describe how hydrogen ion concentration relates to energy production in oxidative phosphorylation. The pH in the intermembrane space is higher than the pH in the mitochondrial matrix. Oxidative phosphorylation relies on the hydrogen ion concentration gradient generated and maintained by the electron transport chain. Hydrogen ions are actively transported out of the mitochondrial matrix. Hydrogen ion concentration is higher in the intermembrane space than in the mitochondrial matrix. Energy is generated as a result of the difference in hydrogen ion concentration between the mitochondrial matrix and the cytoplasm.