In which of the following compounds does hydrogen form ionic compounds?

Out of the given compounds, only NaH (sodium hydride) contains ionic bonds involving hydrogen. In NaH, hydrogen has a negative charge (H\(^-\)) and sodium has a positive charge (Na\(^+\)). This results in the formation of an ionic compound. In the other compounds, hydrogen forms covalent bonds. In CH\(_4\) (methane), hydrogen shares electrons with carbon to form four covalent bonds. In HCl (hydrogen chloride), hydrogen shares electrons with chlorine to form a single covalent bond. In NH\(_3\) (ammonia), hydrogen shares electrons with nitrogen to form three covalent bonds. Therefore, only NaH contains ionic bonds involving hydrogen, while the others have covalent bonds.