Question

(i) \( \text{AgNO}_3 + \text{NaCl} \rightarrow \text{NaNO}_3 + \text{AgCl} \)
(ii) \( \text{K}_2\text{SO}_4 + \text{BaCl}_2 \rightarrow \text{BaSO}_4 + 2\text{KCl} \)
Which of the following options clearly describes both the reactions?

• A. (i) is double displacement, (ii) is displacement reaction.
• B. Both, (i) and (ii) are displacement reactions and precipitation reactions.
• C. Both, (i) and (ii) are double displacement reactions and precipitation reactions.
• D. (i) is displacement, (ii) is double displacement reaction.

Hint:

Double displacement reactions often result in precipitate formation when one product is insoluble.
Common precipitates: AgCl (white), BaSO\(_4\) (white), PbI\(_2\) (yellow), etc.

Answer 1

The Correct Option is C

To determine the correct description of the reactions given (i) and (ii), let's analyze each reaction step-by-step:

1. Reaction (i): \( \text{AgNO}_3 + \text{NaCl} \rightarrow \text{NaNO}_3 + \text{AgCl} \)
   • This reaction involves the exchange of ions between silver nitrate \(( \text{AgNO}_3 )\) and sodium chloride \(( \text{NaCl} )\).
   • Silver \(( \text{Ag}^+ )\) pairs with chloride \(( \text{Cl}^- )\) to form silver chloride \(( \text{AgCl} )\).
   • Sodium \(( \text{Na}^+ )\) pairs with nitrate \(( \text{NO}_3^- )\) to form sodium nitrate \(( \text{NaNO}_3 )\).
   • The formation of a precipitate, silver chloride (a white solid), confirms the occurrence of a precipitation reaction.
   • This is classified as a double displacement (or double replacement) reaction, as ions are exchanged between two compounds.
2. Reaction (ii): \( \text{K}_2\text{SO}_4 + \text{BaCl}_2 \rightarrow \text{BaSO}_4 + 2\text{KCl} \)
   • In this reaction, ions are exchanged between potassium sulfate \(( \text{K}_2\text{SO}_4 )\) and barium chloride \(( \text{BaCl}_2 )\).
   • Barium \(( \text{Ba}^{2+} )\) pairs with sulfate \(( \text{SO}_4^{2-} )\) to form barium sulfate \(( \text{BaSO}_4 )\), which precipitates out as a white solid.
   • Potassium \(( \text{K}^+ )\) pairs with chloride \(( \text{Cl}^- )\) to form potassium chloride \(( \text{KCl} )\).
   • As in the first reaction, the precipitation of barium sulfate confirms that this is a precipitation reaction.
   • This is also a double displacement reaction.

Both reactions exhibit the key characteristics of double displacement and precipitation reactions, where two compounds exchange ions, resulting in the formation of an insoluble precipitate.

Therefore, the correct answer is: Both, (i) and (ii) are double displacement reactions and precipitation reactions.