All questions of Alkali Metals- Sodium for JAMB Exam

B

Introduction
Sodium hydrogen trioxocarbonate (IV), also known as sodium bicarbonate or baking soda, is a versatile compound with various uses in daily life. However, one of the options provided in the question does not accurately reflect the use of sodium hydrogen trioxocarbonate (IV). Let's explore each option and identify the correct answer.

Options

a) Baking soda in cooking: Sodium hydrogen trioxocarbonate (IV) is commonly used as a leavening agent in baking. When combined with an acid (such as vinegar or lemon juice) and a liquid, it produces carbon dioxide gas, which helps dough rise and gives baked goods a light and fluffy texture. Therefore, this option is a correct use of sodium hydrogen trioxocarbonate (IV).

b) Antacid for indigestion: Sodium hydrogen trioxocarbonate (IV) is also used as an antacid to relieve symptoms of indigestion. It works by neutralizing excess stomach acid, reducing heartburn and discomfort. This option is also a correct use of sodium hydrogen trioxocarbonate (IV).

c) Fire extinguisher: Sodium hydrogen trioxocarbonate (IV) is not used as a fire extinguisher. Fire extinguishers typically contain different chemicals, such as water, carbon dioxide, or dry powder, which are specifically designed to suppress various types of fires. Therefore, this option is the correct answer to the question.

d) pH regulator in swimming pools: Sodium hydrogen trioxocarbonate (IV) can be used as a pH regulator in swimming pools. It helps to maintain the desired pH level in the pool water, ensuring the water is safe and comfortable for swimmers. This option is not the correct answer to the question.

Conclusion

In conclusion, the correct answer to the question is option 'c' - Fire extinguisher. Sodium hydrogen trioxocarbonate (IV) is not used as a fire extinguisher, but it is commonly used in cooking as a leavening agent, as an antacid for indigestion, and as a pH regulator in swimming pools.

Reaction of Sodium Hydroxide with Aluminum Ions

When sodium hydroxide (NaOH) reacts with aluminum ions (Al3+), sodium aluminate (NaAlO2) is formed. This reaction can be represented by the following balanced chemical equation:

2NaOH + Al3+ -> NaAlO2 + H2O

Explanation:

1. Formation of Sodium Hydroxide Solution:
Sodium hydroxide is a strong base that dissociates completely in water, forming sodium ions (Na+) and hydroxide ions (OH-). This reaction can be represented as:

NaOH -> Na+ + OH-

2. Dissociation of Aluminum Salt:
Aluminum ions can be obtained from aluminum salts such as aluminum sulfate (Al2(SO4)3) or aluminum chloride (AlCl3). In an aqueous solution, these salts dissociate into their respective ions. For example, aluminum sulfate dissociates as follows:

Al2(SO4)3 -> 2Al3+ + 3SO4^2-

3. Reaction between Sodium Hydroxide and Aluminum Ions:
When sodium hydroxide solution is added to an aqueous solution containing aluminum ions, a precipitation reaction occurs. The hydroxide ions from sodium hydroxide react with the aluminum ions to form a solid precipitate of aluminum hydroxide (Al(OH)3):

Al3+ + 3OH- -> Al(OH)3

4. Formation of Sodium Aluminate:
The reaction between aluminum hydroxide and excess sodium hydroxide leads to the formation of sodium aluminate. This can be represented by the following equation:

2Al(OH)3 + 2NaOH -> 2NaAlO2 + 3H2O

The resulting product, sodium aluminate, is a compound composed of sodium ions and the aluminate ion (AlO2-).

Conclusion:
In summary, when sodium hydroxide reacts with aluminum ions, sodium aluminate is formed. This reaction is important in various applications, such as in the production of aluminum metal and in the treatment of wastewater containing aluminum ions.

Understanding Sodium Chloride Solubility
Sodium chloride (NaCl), commonly known as table salt, is well-known for its solubility in water. Here's a detailed explanation of why option 'C' is the correct answer.
High Solubility in Water
- Sodium chloride is highly soluble in water, which means a significant amount can dissolve in a given volume of water.
- At room temperature, approximately 357 grams of sodium chloride can dissolve in one liter of water. This high solubility is due to the ionic nature of NaCl.
Ionic Dissociation
- When sodium chloride is added to water, it dissociates into its constituent ions: sodium ions (Na+) and chloride ions (Cl-).
- The polar nature of water molecules surrounds these ions, stabilizing them and preventing them from recombining. This process facilitates the dissolution of sodium chloride.
Implications of High Solubility
- The high solubility of sodium chloride in water makes it a vital compound in various applications, including cooking, food preservation, and chemical processes.
- Its solubility allows for effective use in saline solutions for medical and biological purposes.
Conclusion
- In summary, sodium chloride is highly soluble in water, making option 'C' the correct choice.
- The other options are incorrect because they either underestimate its solubility or mistakenly imply that sodium chloride reacts with water to produce a gas, which it does not. Sodium chloride simply dissolves, and no gas is formed in this process.

Understanding Sodium Trioxocarbonate (IV)
Sodium trioxocarbonate (IV), commonly known as sodium carbonate, is a vital chemical compound used in various applications, including glass manufacturing and water treatment.
Chemical Formula
- The correct chemical formula for sodium trioxocarbonate (IV) is Na2CO3.
- This compound consists of two sodium (Na) ions and one carbonate (CO3) ion.
Why Na2CO3?
- The term "trioxocarbonate (IV)" indicates that the compound has a carbonate ion, which contains one carbon atom and three oxygen atoms.
- The Roman numeral IV refers to the oxidation state of carbon in carbonates, which is +4.
Options Analysis
- Option a: Na2CO3 - This is the correct answer. It reflects the composition of sodium carbonate.
- Option b: Na2CO2 - This represents sodium carbonate with an incorrect structure, as it implies a different oxidation state for carbon.
- Option c: NaHCO3 - This is sodium bicarbonate, also known as baking soda, which contains one hydrogen atom and is a different compound.
- Option d: Na2SO4 - This is sodium sulfate, which contains sulfate ions instead of carbonate ions.
Conclusion
The correct answer to the question about sodium trioxocarbonate (IV) is option 'A', Na2CO3. Understanding the composition and distinguishing features of these compounds is essential for chemistry studies, especially in examinations like JAMB.