Problem 16 - Chemistry in 30 days

Question

On the basis of structure, the oxidation of two \(\mathrm{Cl}\) atoms in \(\mathrm{CaOCl}_{2}\) respectively are (a) \(-1\) and \(+1\) (b) \(+2,-2\) (c) \(-2,+2\) (d) \(-1\) and \(+3\)

Step-by-Step Solution

Answer

(a) \(-1\) and \(+1\)

Step 1: Understanding Calcium Oxychloride

Start by examining the compound, \( \text{CaOCl}_2 \), which is commonly known as bleaching powder. The structural formula of calcium oxychloride includes chlorine in two different environments: one as part of a hypochlorite ion (\( \text{ClO}^- \)) and the other as a chloride ion (\( \text{Cl}^- \)).

Step 2: Assessing the Oxidation State of the Chloride Ion

The chloride ion (\( \text{Cl}^- \)) carries an oxidation state of \(-1\) since it is a simple monoatomic ion directly attached to calcium.

Step 3: Evaluating the Oxidation State of the Hypochlorite Ion

In the hypochlorite ion \( \text{ClO}^- \), we start by knowing the overall charge is \(-1\). Oxygen is usually \(-2\) in compounds. Let \( x \) be the oxidation state of chlorine here. So, \( x - 2 = -1 \) gives \( x = +1 \). The chlorine in the hypochlorite ion has an oxidation state of \(+1\).

Step 4: Drawing Conclusion from the Calculations

Now you have one chlorine atom with oxidation state \(-1\) (from chloride ion) and another one with \(+1\) (from hypochlorite ion).

Key Concepts

Calcium Oxychloride

Calcium oxychloride, typically written as \( \text{CaOCl}_2 \), is a fascinating compound as it harbors chlorine atoms in distinct oxidative states. This compound is known better in everyday life as bleaching powder, widely used for disinfection and water treatment. In its structure, calcium is bonded to two chlorine atoms but in two very different roles. This duality is what makes calcium oxychloride so intriguing. Understanding the structural dynamics of \( \text{CaOCl}_2 \) is key to grasping the related oxidation states.

Bleaching Powder

Bleaching powder, or calcium oxychloride, is a powerful disinfectant frequently used in purification processes. When talking about its chemical structure, in \( \text{CaOCl}_2 \), each chlorine atom is involved in different chemical entities. This compound releases chlorine ions in water, contributing to its strong bleach properties.
The chlorine in bleaching powder is potent in eliminating bacteria and other pathogens, making it essential in water treatment facilities. Its usage is not restricted to bleaching textiles and paper, but also extends to sanitation and as a fungicide.

Hypochlorite Ion

The hypochlorite ion, symbolized as \( \text{ClO}^- \), is an anion known for its oxidizing abilities. In \( \text{CaOCl}_2 \), it is part of the chemical balance that enables the compound to exhibit distinct oxidation states.
In a hypochlorite ion, the oxygen carries an oxidation state of \(-2\), while the chlorine is typically \(+1\). This ion is crucial in many bleaching and disinfecting reactions, where it helps break down stains and decompose microbes. Its presence in bleaching powder delivers both bleaching and deodorizing properties, showcasing its multifunctional nature.

Chloride Ion

The chloride ion is represented as \( \text{Cl}^- \) and bears an oxidation state of \(-1\), being a straightforward monoatomic ion. In the context of calcium oxychloride, one of the chlorine atoms assumes this form. The negatively charged ion comes into existence when chlorine gains an electron.
In bleaching powder, the chloride ion is integral for neutralizing charges and ensuring the compound's stability. While simple in its singular state, these ions are crucial in maintaining the overall properties of complex compounds such as \( \text{CaOCl}_2 \), impacting reactivity and stability.