A solution reacts with crushed egg-shells to give a gas that turns lime-water milky. The solution contains:

A. NaCl

B. HCl

C. LiCl

D. KCl

To determine which solution reacts with crushed egg-shells to produce a gas that turns lime-water milky, we need to consider the chemical properties of the options provided. The key here is understanding the reaction that occurs when an acid interacts with calcium carbonate, which is a major component of egg-shells.

Identifying the Reaction

Crushed egg-shells primarily consist of calcium carbonate (CaCO3). When an acid reacts with calcium carbonate, it produces carbon dioxide (CO2) gas, water, and a salt. The reaction can be summarized as follows:

• CaCO3 + 2HCl → CaCl2 + H2O + CO2↑

The carbon dioxide gas produced in this reaction is what turns lime-water (a solution of calcium hydroxide, Ca(OH)2) milky. This happens because the CO2 reacts with the calcium hydroxide to form calcium carbonate, which is insoluble in water and appears as a white precipitate.

Analyzing the Options

Now, let’s evaluate the options given:

• A. NaCl - Sodium chloride is a neutral salt and does not produce any gas when reacting with calcium carbonate.
• B. HCl - Hydrochloric acid is a strong acid that will react with calcium carbonate to produce carbon dioxide, making this option a likely candidate.
• C. LiCl - Lithium chloride is also a salt and does not react with calcium carbonate to produce gas.
• D. KCl - Potassium chloride is another neutral salt that does not react with calcium carbonate.

Conclusion on the Correct Answer

Given this analysis, the only solution that will react with crushed egg-shells to produce carbon dioxide gas, which in turn makes lime-water milky, is B. HCl (hydrochloric acid). This reaction is a classic demonstration of acid-base chemistry and illustrates how acids can react with carbonates to release gases.

Real-World Application

This type of reaction is not just limited to laboratory settings; it can also be observed in nature. For example, when acid rain (which contains dissolved carbon dioxide and other acids) falls on limestone (which is primarily calcium carbonate), it can lead to the formation of caves and other geological features over time.

To determine which solution reacts with crushed egg-shells to produce a gas that turns lime-water milky, we need to analyze the chemical reactions involved. The key here is understanding what the crushed egg-shells are made of and how they interact with different solutions.

Composition of Egg-Shells

Crushed egg-shells primarily consist of calcium carbonate (CaCO₃). When calcium carbonate reacts with an acid, it produces carbon dioxide gas (CO₂), which is the gas that turns lime-water milky. Lime-water is a dilute solution of calcium hydroxide (Ca(OH)₂), and when CO₂ is bubbled through it, it forms calcium carbonate, which is insoluble and causes the milky appearance.

Identifying the Acidic Solution

Now, let’s look at the options provided:

• A. NaCl - Sodium chloride is a neutral salt and does not produce any gas when reacting with calcium carbonate.
• B. HCl - Hydrochloric acid is a strong acid that reacts with calcium carbonate to produce carbon dioxide, water, and sodium chloride.
• C. LiCl - Lithium chloride is also a neutral salt and will not react with calcium carbonate to produce gas.
• D. KCl - Potassium chloride is another neutral salt that does not react with calcium carbonate.

Analyzing the Reaction

The reaction between hydrochloric acid (HCl) and calcium carbonate (CaCO₃) can be represented as follows:

CaCO₃ + 2 HCl → CaCl₂ + H₂O + CO₂↑

In this reaction, the production of carbon dioxide gas (CO₂) is what we are looking for, as it is the gas that will turn lime-water milky.

Conclusion

Based on the analysis, the correct answer is B. HCl. This solution will react with crushed egg-shells, releasing carbon dioxide gas that causes the lime-water to become milky. Understanding these reactions helps in grasping the fundamental concepts of acids, bases, and their interactions with carbonates.