Question

A variety of water which contains soluble salts of \(\mathrm{Ca}\) and \(\mathrm{Mg}\) is known as (a) soft water (b) heavy water (c) conductivity water (d) hard water

Short answer

The water is known as hard water.

Step-by-step solution

Understanding the Problem

We need to identify a type of water based on its composition. Specifically, it contains soluble salts of calcium (Ca) and magnesium (Mg). The exercise presents four options: soft water, heavy water, conductivity water, and hard water.

Reviewing Definitions

Let's review the definitions of the types of water listed: - Soft water: Has low concentrations of ions, particularly those of calcium and magnesium. - Heavy water: Contains a higher proportion of the isotope deuterium (instead of normal hydrogen) and doesn't deal with salt content. - Conductivity water: Refers to purified water used in applications needing minimal impurities but is not characterized by calcium/magnesium content. - Hard water: Contains high concentrations of dissolved minerals, primarily calcium and magnesium salts.

Relating Definitions to the Problem

The problem mentions the presence of soluble salts of calcium (Ca) and magnesium (Mg). From the reviewed definitions, hard water is known to contain these mineral salts.

Selecting the Correct Option

Based on the presence of calcium and magnesium, we can conclude that the variety of water described in the problem is hard water.

Key concepts

Calcium and Magnesium Salts

Understanding the role of calcium and magnesium salts in water is crucial to distinguish different types of water. These salts often form when calcium or magnesium ions bond with various anions, leading to compounds like calcium carbonate (\(\text{CaCO}_3\)) or magnesium sulfate (\(\text{MgSO}_4\)).

In water, calcium and magnesium salts are considered as hardness minerals. They dissolve from rocks and soil through which water flows, embedding themselves in the water composition.

• Calcium salts can originate from limestone or gypsum.
• Magnesium salts often come from dolomite rocks.

These minerals dissolve in water more readily at high levels of carbon dioxide, which is often present in natural water bodies.

While these salts are not harmful for consumption, they can cause issues in household systems, such as causing scale buildup in pipes and on heating elements.

Water Composition

Water's composition describes the type and concentration of substances dissolved in it. The basic composition of water is two hydrogen atoms combined with one oxygen atom, forming \(\text{H}_2\text{O}\). Natural water sources, however, contain various dissolved minerals and gases that define their specific character.

Common minerals include:

• Sodium (Na) and potassium (K), often found in soft water.
• Calcium (Ca) and magnesium (Mg) salts, which contribute to water hardness.
• Iron (Fe) and manganese (Mn), which can cause staining and affect taste.

Water composition is critical in determining the suitability of water for specific uses like drinking, cooking, and industrial applications. For example, high mineral content can be beneficial for certain health applications but detrimental for appliances.

Understanding the composition helps in treating and processing water to achieve desired qualities for different needs.

Types of Water

Water can be categorized into different types based on its mineral content and specific uses. Here are some major types:

• Soft Water: Characterized by low concentrations of calcium and magnesium ions. It does not cause the same scaling issues that hard water does, making it more suitable for cleaning and household appliances.
• Hard Water: Contains high levels of calcium and magnesium. These minerals cause the water to be "hard," which can lead to scale buildup that interferes with plumbing and heating systems.
• Heavy Water: Distinct from regular water, heavy water contains a higher concentration of deuterium. It is not commonly found in everyday settings and is mainly used in nuclear reactors.
• Conductivity Water: Also known as deionized or distilled water, this water is purified to remove ions so that it does not conduct electricity. It is primarily used in laboratories and industrial applications where impurities must be minimized.

Each type of water has unique applications and implications on health, industry, and daily living.