Using the criteria for double displacement reactions and the solubility table b- KOH+HCl? c-CaCO3 + HCl ? d- Ba(NO3)2+NmPO1-> e- BiCl3+ NaOH ?
The correct answer and explanation is :
In double displacement reactions, also known as metathesis reactions, two ionic compounds exchange their ions to form new products. The key criteria for determining whether a double displacement reaction will occur include:
- The formation of a precipitate (an insoluble product).
- The formation of a gas (often released during the reaction).
- The formation of water (as in acid-base neutralization reactions).
Let’s break down each reaction using these criteria:
a) KOH + HCl → KCl + H₂O
- Type: Neutralization (acid-base reaction).
- KOH is a strong base, and HCl is a strong acid. When combined, they form water (H₂O) and potassium chloride (KCl), which is soluble in water. This is a neutralization reaction, which always results in water as the product.
- Conclusion: The reaction occurs because a neutralization between the acid and base produces water.
b) CaCO₃ + 2HCl → CaCl₂ + CO₂ + H₂O
- Type: Double displacement with gas formation.
- Calcium carbonate (CaCO₃) reacts with hydrochloric acid (HCl). The products are calcium chloride (CaCl₂), carbon dioxide (CO₂), and water. Carbon dioxide is a gas that escapes from the solution.
- Conclusion: The reaction occurs because CO₂ gas is formed, which escapes the solution, driving the reaction.
c) Ba(NO₃)₂ + 2NaPO₄ → Ba₃(PO₄)₂ + 2NaNO₃
- Type: Precipitation reaction.
- Barium nitrate (Ba(NO₃)₂) and sodium phosphate (NaPO₄) react to form barium phosphate (Ba₃(PO₄)₂), which is insoluble in water, and sodium nitrate (NaNO₃), which is soluble. The insolubility of barium phosphate leads to its formation as a precipitate.
- Conclusion: This reaction occurs due to the formation of an insoluble precipitate (Ba₃(PO₄)₂).
d) BiCl₃ + 3NaOH → Bi(OH)₃ + 3NaCl
- Type: Precipitation reaction.
- Bismuth chloride (BiCl₃) reacts with sodium hydroxide (NaOH). The product bismuth hydroxide (Bi(OH)₃) is insoluble in water and precipitates out, while sodium chloride (NaCl) remains soluble.
- Conclusion: This reaction occurs due to the formation of an insoluble precipitate (Bi(OH)₃).
In summary:
- a) results in water, b) produces gas (CO₂), c) produces a precipitate (Ba₃(PO₄)₂), and d) forms a precipitate (Bi(OH)₃). These are all valid double displacement reactions based on the criteria of precipitate formation, gas production, or water formation.