Which of the following elements can form a compound with hydrogen where hydrogen has a positive valency?

When hydrogen forms a compound with carbon, it exhibits a positive valency. In such compounds, hydrogen is bonded to carbon via a covalent bond, where the electron pair is shared between the two atoms. Since carbon is more electronegative than hydrogen, it attracts the shared electrons more strongly, resulting in a partial positive charge on the hydrogen atom. This is true for various organic compounds, such as hydrocarbons (e.g., methane, CH4), where hydrogen is bonded to carbon and exhibits a positive valency. In contrast, when hydrogen forms compounds with chlorine, oxygen, or nitrogen, it tends to exhibit a negative valency due to the higher electronegativity of these elements compared to hydrogen.