How do non-metals react with hydrogen? Explain with an example.

42 Name two metals which can, however, liberate hydrogen gas from very dilute nitric acid. 43 How do metals react with hydrogen? Explain with an example. 44 What happens when calcium reacts with chlorine? Write an equation for the reaction which takes place. 44 What happens when magnesium reacts with very dilute nitric acid? Write an equation for the reaction involved.