Question

Identify the precipitation reaction.
1. Hydrogen + oxygen → water
2. Sodium + chlorine → sodium chloride
3. Sodium chloride + silver nitrate → silver chloride + sodium nitrate
4. Calcium carbonate → calcium oxide + carbon dioxide

Answer 1

Correct Answer - Option 3 : Sodium chloride + silver nitrate → silver chloride + sodium nitrate

Concept:

Chemical Reactions:

• A process in which one or more compounds are formed as products completely different from the reacting substances is known as a chemical reaction.
• There is generally a change in heat, color, or appearance when a chemical reaction takes place.
• The evolution of gas may also occur.
• A chemical reaction may be reversible or irreversible in nature.
• Chemical changes occur in chemical reactions.

Types of Chemical Reactions-

Different types of reactions are

• Combustion reaction
• Decomposition reaction
• Neutralization reaction
• Precipitation or Double-Displacement Reaction

Explanation:

• Precipitation reactions refer to the formation of insoluble salt when two solutions containing soluble salts are mixed. The insoluble salt that comes out of the solution is known as a precipitate, hence the name of the reaction.
• Precipitation reactions can help to determine the identity of different ions in the solution.

• NaCl + AgNO₃ ​→ AgCl + NaNO₃​

Mol :     1 mol     1 mol        1 mol      1 mol

Mass:   58.5 g     170 g      143.5 g    85 g

• In the reaction above, AgCl is formed as a precipitate.
• Hence. the reaction Sodium chloride + silver nitrate → silver chloride + sodium nitrate is a precipitation reaction.

• As two hydrogens and oxygen exchange electrons by covalent bonds, a water molecule is formed.
  • 2H₂ + O₂ → 2H₂O
• Examples are the reactions in which sodium (Na) interacts with chlorine (Cl₂) to form sodium chloride or table salt (NaCl). The reaction of sodium with chlorine to sodium chloride is an example of a mixed reaction.
  • 2Na + Cl₂ → 2NaCl
  • CaCO₃ → CaO+CO₂