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