Precipitation Reaction MCQs Quiz | Class 10

This quiz covers Class X Science (Code 086), Unit I: Chemical Substances – Nature and Behaviour. It focuses on precipitation reactions, precipitate formation, colors of precipitates, and observation-based questions. Test your understanding, check your score, and download the answer key PDF for revision.

Overview of Precipitation Reactions

A precipitation reaction is a type of double displacement reaction where two soluble salts react in an aqueous solution to form one soluble product and one insoluble solid product. This insoluble solid is known as a precipitate. These reactions are crucial for identifying ions in qualitative analysis.

Key Concepts

  • Definition: Reaction in which an insoluble substance (precipitate) is formed.
  • General Equation: AB(aq) + CD(aq) -> AD(aq) + CB(s)
  • Observation: The formation of the precipitate is often accompanied by a distinct color change or cloudiness in the solution.

Common Precipitates and Colors

Reactants Precipitate Formed Color of Precipitate
Lead Nitrate + Potassium Iodide Lead Iodide (PbI2) Yellow
Barium Chloride + Sodium Sulphate Barium Sulphate (BaSO4) White
Silver Nitrate + Sodium Chloride Silver Chloride (AgCl) White
Copper Sulphate + Sodium Hydroxide Copper Hydroxide (Cu(OH)2) Pale Blue

Quick Revision Points

  • The symbol (s) or a downward arrow is used to represent a precipitate in a chemical equation.
  • Most precipitation reactions involve the exchange of ions between reactants.
  • Not all double displacement reactions form precipitates; some form gas or water (neutralization).

Extra Practice Questions

  1. What is the color of the precipitate formed when Hydrogen Sulphide gas is passed through Copper Sulphate solution? (Ans: Black CuS)
  2. Name the precipitate formed when Carbon Dioxide is passed through Lime Water. (Ans: Calcium Carbonate)
  3. Write the formula of the white precipitate formed in the reaction between AlCl3 and NH4OH. (Ans: Al(OH)3)
  4. Is the reaction between acid and base a precipitation reaction? (Ans: usually no, it is neutralization)
  5. What happens when you mix Lead Nitrate and Potassium Nitrate? (Ans: No reaction, both products are soluble)