Problem 94 - A Complete Resource Book in Chemistry for JEE Main

Question

The gases respectively absorbed by alkaline pyrogallol and oil of cinnamon are (a) \(\mathrm{O}_{2}, \mathrm{O}_{3}\) (b) \(\mathrm{N}_{2} \mathrm{O}, \mathrm{O}_{3}\) (c) \(\mathrm{SO}_{2}, \mathrm{CH}_{4}\) (d) \(\mathrm{O}_{3}, \mathrm{CH}_{4}\)

Step-by-Step Solution

Answer

The correct answer is (a) \(\mathrm{O}_{2}, \mathrm{O}_{3}\).

Step 1: Understand the Role of Alkaline Pyrogallol

Alkaline pyrogallol is a solution known for its ability to absorb oxygen (\(\mathrm{O}_{2}\)). It reacts with oxygen to form a brownish substance due to the oxidation process. Therefore, the gas absorbed by alkaline pyrogallol is \(\mathrm{O}_{2}\).

Step 2: Understand the Absorption Behavior of Oil of Cinnamon

Oil of cinnamon is known for absorbing ozone (\(\mathrm{O}_{3}\)) rather than other gases like methane (\(\mathrm{CH}_{4}\)) or sulfur dioxide (\(\mathrm{SO}_{2}\)). This property is utilized in chemical analysis to specifically identify and measure \(\mathrm{O}_{3}\).

Step 3: Identify the Right Option

From Steps 1 and 2, we know that alkaline pyrogallol absorbs \(\mathrm{O}_{2}\) and oil of cinnamon absorbs \(\mathrm{O}_{3}\). Comparing with the given options: \(\mathrm{O}_{2}\) and \(\mathrm{O}_{3}\) are absorbed by alkaline pyrogallol and oil of cinnamon, respectively. Look for the option matching (\(\mathrm{O}_{2}, \mathrm{O}_{3}\)). The correct choice is (a).

Key Concepts

Alkaline Pyrogallol

Alkaline pyrogallol is a fascinating solution crucial in various chemical applications, especially for absorbing oxygen. It is essentially pyrogallol dissolved in an alkaline medium like potassium hydroxide. This solution is well known for absorbing oxygen from its surroundings. When oxygen is present, it reacts with alkaline pyrogallol, resulting in the formation of a brownish color. This reaction is an oxidation process where the pyrogallol is oxidized by the oxygen it absorbs.

• The absorption ability of alkaline pyrogallol is particularly useful in laboratory settings to remove oxygen from a sample.
• It’s also used in respiratory gas analysis and in the calibration of gas measurement instruments.
• The reaction is specific to oxygen, which makes alkaline pyrogallol a reliable agent for identifying and quantifying oxygen in mixtures.

Understanding how alkaline pyrogallol operates is essential for recognizing its role in chemical processes and its use in scientific research.

Oil of Cinnamon

Oil of cinnamon, derived from the bark of cinnamon trees, is not only known for its aromatic properties but also for its ability to absorb ozone. This essential oil is a complex compound that reacts with certain gases, particularly ozone, which is a reactive form of oxygen. In analytical chemistry, oil of cinnamon is utilized for its specificity in absorbing ozone.

• When oil of cinnamon comes in contact with \(\mathrm{O}_3\), it effectively neutralizes and reduces the gas.
• This feature is valuable in scenarios where the removal or measurement of ozone is necessary, such as environmental testing.
• Its use extends to safety applications where ozone levels need to be monitored and controlled.

Thus, oil of cinnamon proves to be an effective tool in absorbing ozone, making it invaluable in certain chemical analyses and environmental studies.

Oxygen Absorption

Oxygen absorption is a remarkable phenomenon where substances like alkaline pyrogallol remove free oxygen from a surrounding atmosphere. This process is critical in many scientific and industrial applications. Oxygen absorption can occur through various mechanisms, including chemical reactions and physical absorption.

• In the case of alkaline pyrogallol, oxygen absorption involves a chemical reaction, where oxygen molecules interact with the solution to form new products.
• This ability is utilized in food packaging, medical applications, and any area where controlling oxygen levels is crucial.
• It’s also used in gas analysis methods to isolate oxygen from other atmospheric gases.

Mastering the concept of oxygen absorption helps in understanding its practical applications, especially in scenarios where oxygen's presence needs management or complete removal.

Ozone Absorption

Ozone absorption deals with the intake or removal of ozone gas from an environment, a task that oil of cinnamon can perform effectively. Ozone is a molecule composed of three oxygen atoms (12), and it is much more reactive than regular oxygen 02 atoms. Due to its oxidative nature, ozone can cause damage to living organisms, so controlling its levels in certain environments is important.

• Ozone absorption by substances like oil of cinnamon is important for maintaining air quality and protecting materials from oxidative damage.
• Regular monitoring of ozone levels, and using absorptive materials, helps in environmental protection and industrial processes.
• Ozone absorption techniques are critical in places where ozone generation results from industrial activities or ozone applications in water treatment.

Understanding how substances like oil of cinnamon absorb ozone helps in applying this knowledge to environmental, health, and industrial contexts, ensuring safety and efficacy in ozone management.