Chemical reactions entangle chemical changes that lead to the formation of a new compound under specific conditions. A chemical reaction that combines two ionic bonds in an aqueous solution leads to the formation of an insoluble salt is known as a precipitation reaction. The insoluble salts formed during precipitation reactions are known as a precipitate.
Example: An aqueous solution of silver nitrate reacts with sodium chloride to form a precipitate of silver chloride and an aqueous solution of sodium nitrate.
AgNO3 (aq) + NaCl (aq) → AgCl (s) + NaNO3 (aq)
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Definition: A chemical reaction that combines two ionic bonds in an aqueous solution leads to the formation of an insoluble salt is known as a precipitation reaction. The insoluble salts formed during precipitation reactions are known as a precipitate. |
Precipitation Chemistry Questions with Solutions
Q1. What precipitate will form when silver nitrate reacts with sodium chloride?
(a) Silver chloride
(b) Silver nitrite
(c ) Both (a) and (b)
(d) None of the above
Answer: (a) Silver chloride will form when silver nitrate reacts with sodium chloride.
Q2. True or false: precipitation reactions are ionic reactions.
(a) True
(b) False
(c ) Neither true nor false
(d) None of the above
Answer: (a) True, Precipitation reactions are ionic reactions.
Q3. True or false: precipitation reactions are not temperature-dependent.
(a) True
(b) False
(c ) Neither true nor false
(d) None of the above
Answer: (b) False, precipitation reactions are temperature-dependent.
Q4. True or false: precipitation reactions are dependent on solution concentration.
(a) True
(b) False
(c ) Neither true nor false
(d) None of the above
Answer: (a) True, precipitation reactions are dependent on solution concentration.
Q5. EDTA method is also known as _________
(a) Complexometric titration
(b) Complex titration
(c ) Complement titration
(d) Complexion titration
Answer: (a) EDTA method is also known as complexometric titration.
Q6. Identify the precipitation reaction.
(a) Hydrogen + Oxygen → Water
(b) Sodium + Chlorine → Sodium chloride
(c ) Sodium chloride + Silver nitrate → Sodium nitrate + Silver chloride
(d) Calcium carbonate → Calcium oxide + Carbon dioxide
Answer: (c ) Sodium chloride + Silver nitrate → Sodium nitrate + Silver chloride is an example of precipitation reaction.
Q7. What is a precipitation reaction?
Answer: A chemical reaction that combines two ionic bonds in an aqueous solution leads to the formation of an insoluble salt is known as a precipitation reaction. The insoluble salts formed during precipitation reactions are known as a precipitate.
Q8. Give any two applications of precipitation reactions?
Answer: A chemical reaction that combines two ionic bonds in an aqueous solution leads to the formation of an insoluble salt is known as a precipitation reaction. The insoluble salts formed during precipitation reactions are known as a precipitate.
There are a lot of applications of precipitation reactions. A few of them are mentioned below.
1. It helps determine the specific elements present in the given solution.
2. It is useful in extracting magnesium from seawater.
Q9. Give any two examples of the precipitation reactions.
Answer: A chemical reaction that combines two ionic bonds in an aqueous solution leads to the formation of an insoluble salt is known as a precipitation reaction. The insoluble salts formed during precipitation reactions are known as a precipitate.
Examples of precipitation reactions:
1. An aqueous solution of silver nitrate reacts with potassium chloride to form a precipitate of silver chloride and an aqueous solution of potassium nitrate.
AgNO3 (aqueous) + KCl (aqueous) → AgCl (precipitate) + KNO3 (aqueous)
2. An aqueous solution of silver nitrate reacts with sodium chloride to form a precipitate of silver chloride and an aqueous solution of sodium nitrate.
AgNO3 (aqueous) + NaCl (aqueous) → AgCl (precipitate) + NaNO3 (aqueous)
Q10. What is the effect of temperature on the precipitation reaction?
Answer: A change in the temperature will affect the occurrence of a precipitation reaction. With an increase in the temperature, the solubility of ionic compounds increases, leading to an increase in the occurrence of a precipitation reaction.
Q11. What is a precipitating agent?
Answer: A chemical reagent responsible for forming precipitates is known as a precipitating agent or precipitant.
Calcium hydroxide (lime) or sodium hydroxide (caustic soda) are common examples of precipitating agents.
Q12. Why is precipitation important in chemistry?
Answer: Precipitation plays a critical role in chemistry. It is useful in
1. Purification
2. Removing or recovering salts
3. Making pigments
4. Identify substances in qualitative analysis
Q13. Is precipitation a sign of a chemical reaction?
Answer: Yes, a precipitate’s formation is a chemical reaction sign.
Example: When an aqueous solution of silver nitrate is mixed with sodium chloride, a chemical reaction occurs leading to the formation of a precipitate of silver chloride and an aqueous solution of sodium nitrate is formed.
AgNO3 (aqueous) + NaCl (aqueous) → AgCl (precipitate) + NaNO3 (aqueous)
Q14. Mention the formula, name and physical state of the products of the following precipitation reaction.
AgNO3 (aq) + NaCl (aq) → AgCl (s) + NaNO3 (aq)
Answer:
Reaction: AgNO3 (aq) + NaCl (aq) → AgCl (s) + NaNO3 (aq)
Name: AgCl (Silver chloride)
NaNO3 (Sodium nitrate)
Physical state of AgCl is solid while NaNO3 is aqueous in nature.
Q15. Under what conditions will a precipitate form?
Answer: A precipitate will form if the resulting compound is insoluble in water. For example, an aqueous solution of silver nitrate reacts with potassium chloride to form a precipitate of silver chloride and an aqueous solution of potassium nitrate.
AgNO3 (aqueous) + KCl (aqueous) → AgCl (precipitate) + KNO3 (aqueous)
Practise Questions on Precipitation
Q1. Why do precipitation reactions occur?
Q2. What is the effect of pH on the precipitation reaction?
Q3. Is a precipitate soluble?
Q4. How will you differentiate between precipitation reaction and agglutination?
Q5. What is the effect of the degree of dissociation on the precipitation reaction?
Click the PDF to check the answers for Practice Questions.
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