H2Se is the chemical formula for hydrogen selenide, a weak acid that forms when hydrogen reacts with selenium.
KH: Potassium hydride (KH) is an ionic compound formed by the reaction of potassium and hydrogen. It is a stronger base compared to H2Se.
AsH3: Arsine (AsH3) is a toxic gas with a garlic-like odor. It is a weaker acid compared to H2Se.
Hydrogen bromide (HBr) is a strong acid formed by the reaction of hydrogen and bromine. It is much stronger than H2Se in terms of acidity.