Question

When zeolite, which is hydrated sodium aluminium silicate, is treated with hard water the sodium ions are exchanged with: 1\. \(\mathrm{H}^{+}\) ions 2\. \(\mathrm{Ca}^{2+}\) ions 3\. \(\mathrm{SO}_{4}^{-2}\) ions 4\. \(\mathrm{Mg}^{2+}\) ions (a) 2,4 (b) \(1,2,3\) (c) \(2,4,5\) (d) All are correct

Short answer

The sodium ions are exchanged with \(\mathrm{Ca}^{2+}\) and \(\mathrm{Mg}^{2+}\) ions (option a).

Step-by-step solution

Understanding Zeolite Exchange

Zeolite is a hydrated sodium aluminium silicate. Its primary function in water treatment is to soften hard water by exchanging sodium ions (Na\(^+\)) with hard water ions, which are usually calcium (Ca\(^{2+}\)) and magnesium (Mg\(^{2+}\)) ions, leading to the removal of hardness-causing ions.

Identifying the Relevant Ions

In the context of the problem, we need to identify which ions are typically exchanged with sodium ions in zeolite softening. The common hard water ions exchanged are calcium (Ca\(^{2+}\)) and magnesium (Mg\(^{2+}\)).

Evaluating the Options

We analyze the options provided:1. \(\mathrm{H}^{+}\) ions are not related to hard water ion exchange.2. \(\mathrm{Ca}^{2+}\) ions are indeed exchanged in the zeolite process.3. \(\mathrm{SO}_{4}^{-2}\) ions are not typically part of the zeolite ion exchange process.4. \(\mathrm{Mg}^{2+}\) ions are exchanged during zeolite softening.

Choose the Correct Answer

Examining the options, option (a) 2,4 fits the description since \(\mathrm{Ca}^{2+}\) and \(\mathrm{Mg}^{2+}\) are the ions involved in the zeolite exchange process.

Key concepts

Water Softening

Water softening is a process that removes minerals responsible for water hardness, mainly calcium and magnesium ions. When water contains high levels of these minerals, it is termed as "hard water." Hard water can cause a variety of problems in households and industries, such as scaling in pipes and appliances, reducing soap efficiency, and leaving residue on dishes and surfaces.

Zeolite, a naturally occurring mineral made up of hydrated sodium aluminium silicate, is a common choice in water softening systems. It works on the principle of ion exchange. In this process, the hard water passes through a zeolite medium, where sodium ions from the zeolite swap places with calcium and magnesium ions in the water.

• This exchange effectively removes the minerals causing hardness.
• The result is softened water that is less likely to cause scaling or interfere with soaps and detergents.
• Over time, zeolite can be regenerated by flushing with a concentrated salt solution, restoring its sodium content for further use.

Water softening is vital in regions with hard water to enhance the lifespan of plumbing, appliances, and improve the effectiveness of cleaning products.

Calcium Ions

Calcium ions, \(\mathrm{Ca}^{2+}\), are one of the primary contributors to water hardness. These ions are typically dissolved from mineral deposits such as limestone and continue to be present in groundwater and surface water sources.

Calcium in water can lead to the formation of calcium carbonate, a common scaling mineral, especially when heated. This scaling can coat the interior of pipes, heaters, and other household appliances, dramatically reducing their efficiency and lifespan.

Using a process like zeolite ion exchange is essential to mitigate these problems. When hard water flows over the zeolite resin bed, calcium ions in the water exchange places with sodium ions initially bound to the zeolite. This action removes calcium from the water, effectively softening it.

• Reduced levels of calcium ions prevent scaling.
• The softened water makes household cleaning agents perform better.
• Also, it reduces maintenance costs for appliances and plumbing systems.

Understanding the impact of calcium ions helps in appreciating the importance of water softening methods like zeolite ion exchange.

Magnesium Ions

Magnesium ions, \(\mathrm{Mg}^{2+}\), along with calcium ions, are major contributors to the hardness of water. They enter water supplies mainly through natural leaching from geological formations rich in magnesium-containing minerals such as dolomite.

Much like calcium, magnesium ions can cause adverse effects in both domestic and industrial settings. They are often responsible for building up limescale, which can clog pipes, reduce heat transfer efficiency, and cause damage to appliances such as boilers and kettles. Additionally, magnesium makes soap less effective by forming insoluble soap scum.

• To alleviate these effects, magnesium ions are targeted during water softening processes.
• When passed through zeolite, magnesium ions are exchanged for sodium ions.
• This exchange significantly reduces water hardness, providing all the advantages of soft water usage.

With the removal of magnesium ions, water treatment systems produce water that is less prone to cause issues associated with hardness. This makes the process of zeolite ion exchange incredibly beneficial.

Hard Water Treatment

Hard water treatment is crucial for ensuring water quality and functionality in both residential and commercial settings. The presence of calcium and magnesium ions in water defines its hardness and presents challenges that necessitate mitigation.

Among the different methods available, ion exchange using zeolite is one of the most effective and widely adopted. This method targets the main hard water ions and facilitates their removal. Through the exchange process inside a zeolite softener, sodium ions on the zeolite are traded with calcium and magnesium ions in the water.

• The result is water that is soft, with reduced scaling potential.
• This soft water is highly beneficial; it prevents mineral build-up in plumbing and appliances.
• Furthermore, it improves soap efficiency, leaving clothes and dishes cleaner.

By understanding and applying hard water treatment solutions like zeolite ion exchange, both residential and industrial users can significantly enhance their water systems, improving longevity and performance.