Short Answer:

Nonmetals react with hydrogen to form covalent compounds called hydrides. These reactions involve the sharing of electrons so that both hydrogen and the nonmetal achieve stable electron configurations.

For example, chlorine reacts with hydrogen to form hydrogen chloride (HCl), and oxygen reacts with hydrogen to form water (H₂O). These reactions are important in chemical industries, biological systems, and everyday life because the resulting compounds have wide applications.

Detailed Explanation:

Reaction of Nonmetals with Hydrogen

Nonmetals have high electronegativity and typically gain or share electrons rather than losing them. When nonmetals react with hydrogen, they form covalent hydrides where electrons are shared between hydrogen and the nonmetal atom. These reactions are usually exothermic and often occur under controlled temperature and pressure conditions, depending on the nonmetal.

Formation of Hydrides

1. Covalent Bonding:
   • Nonmetals have 4–7 valence electrons and hydrogen has 1 valence electron.
   • By sharing electrons, nonmetals complete their octet while hydrogen attains a stable duet (2 electrons).
2. Examples of Nonmetal Hydrides:
   • Hydrogen Chloride (HCl):
     H₂ + Cl₂ → 2HCl
     • Chlorine shares one electron with hydrogen forming a single covalent bond.
   • Water (H₂O):
     H₂ + ½O₂ → H₂O
     • Oxygen shares electrons with two hydrogen atoms, forming polar covalent bonds.
   • Ammonia (NH₃):
     3H₂ + N₂ → 2NH₃ (Haber process)
     • Nitrogen shares three pairs of electrons with hydrogen atoms to form three covalent bonds.
   • Hydrogen Sulfide (H₂S):
     H₂ + S → H₂S
     • Sulfur shares electrons with two hydrogen atoms forming covalent bonds.
3. Nature of Bonds:
   • The bonds formed are polar or nonpolar covalent, depending on the electronegativity difference between hydrogen and the nonmetal.
   • Example: HCl is polar, H₂ is nonpolar.

Factors Affecting Reaction

1. Reactivity of Nonmetal:
   • Highly reactive nonmetals like fluorine react vigorously with hydrogen even at room temperature.
   • Less reactive nonmetals like nitrogen require high temperature, pressure, or catalysts.
2. Temperature and Pressure:
   • Some hydrides are formed easily at room temperature (HCl), while others need industrial conditions (NH₃ formation).
3. Catalysts:
   • Certain reactions, like ammonia formation, require iron catalysts to increase yield.

Properties and Importance of Hydrides

1. Acidic Nature:
   • Many nonmetal hydrides, such as HCl, H₂S, and HBr, dissolve in water to produce acids.
2. Industrial Applications:
   • HCl is used in chemical synthesis and cleaning.
   • NH₃ is essential for fertilizers and industrial chemicals.
   • H₂O is vital for all life processes.
3. Biological Importance:
   • Water is necessary for cellular reactions.
   • Ammonia is used in nitrogen metabolism in plants and animals.
4. Environmental Role:
   • Hydrides like H₂O and H₂S play a role in natural cycles and ecosystems.

Summary

Nonmetals react with hydrogen to form covalent compounds called hydrides. These reactions involve electron sharing and result in molecules like HCl, H₂O, NH₃, and H₂S, which have important industrial, biological, and environmental applications.

Conclusion:

The reaction of nonmetals with hydrogen is essential for forming stable covalent compounds that are vital for life, industry, and chemical processes. Understanding these reactions helps explain the formation of acids, water, ammonia, and other hydrides that are widely used in daily life and scientific applications.