Question

Which statement is consistent about carbon monoxide? (1) One of its main industrial uses is in the synthesis of methanol, \(\mathrm{CH}_{3} \mathrm{OH}\). (2) Toxicity of CO results from its ability to bond strongly to iron (II) atom in haemoglobin. (3) It is formed by burning carbon or hydrocarbon in excess oxygen (4) It is a colourless, odourless and toxic gas. (a) 2,4 (b) \(1,2,4\) (c) \(1,2,3\) (d) \(2,3,4\)

Short answer

(b) 1, 2, 4

Step-by-step solution

Analyze Statement 1

Statement 1 states that carbon monoxide (CO) is used in the synthesis of methanol (\( \mathrm{CH}_3 \mathrm{OH} \)). This is true, as CO and hydrogen gas are used in the industrial synthesis process to produce methanol.

Evaluate Statement 2

Statement 2 suggests the toxicity of CO comes from its strong bonding with the iron (II) atom in hemoglobin. This is correct, as CO binds with hemoglobin to form carboxyhemoglobin, which prevents oxygen transport in the blood.

Assess Statement 3

Statement 3 claims that CO is formed by burning carbon or hydrocarbons in excess oxygen. This is incorrect; CO is actually produced when carbon or hydrocarbons are burned in a limited supply of oxygen, not in excess.

Check Statement 4

Statement 4 describes CO as a colorless, odorless, and toxic gas. This is correct and a well-known characteristic of carbon monoxide.

Determine the Consistent Statements

By evaluating the statements: Statement 1 is consistent, Statement 2 is consistent, Statement 3 is incorrect, and Statement 4 is consistent. Thus, the correct consistent statements are 1, 2, and 4.

Key concepts

Methanol Synthesis

Methanol, a simple alcohol with the formula \( \mathrm{CH}_3 \mathrm{OH} \), plays a crucial role in various industrial applications. The synthesis of methanol is an essential chemical process where carbon monoxide (CO) is prominently involved. Typically, methanol is produced by reacting carbon monoxide and hydrogen gas in a catalytic environment. Here’s how the process works efficiently:

• The core reaction is expressed by the equation: \( \mathrm{CO} + 2 \mathrm{H}_2 \rightarrow \mathrm{CH}_3 \mathrm{OH} \).
• This synthesis occurs at high pressures and temperatures and often uses catalysts like copper, zinc oxide, and alumina to speed up the reaction.
• Methanol synthesis is significant as methanol is used in the manufacturing of various chemicals, as a fuel additive, and in antifreeze.

By using carbon monoxide in this manner, industries can produce methanol efficiently and sustainably, showcasing how essential CO is in industrial chemistry.

Toxicity and Hemoglobin Interaction

Carbon monoxide’s danger largely stems from its interaction with hemoglobin in the blood. Hemoglobin is the protein in red blood cells responsible for transporting oxygen from the lungs to the rest of the body. However, CO can dramatically interfere with this process:

• CO binds with hemoglobin to form carboxyhemoglobin, a compound significantly more stable than the usual hemoglobin-oxygen bond.
• As carboxyhemoglobin forms, it inhibits oxygen binding and transport, effectively depriving the body’s tissues and organs of essential oxygen.
• This bonding is dangerous even at low atmospheric concentrations of CO, making it a potent and insidious poison.

Understanding this interaction is crucial for safety and healthcare, especially in environments where CO exposure is possible. Quick treatment is vital to prevent serious health consequences.

Combustion Reactions

Combustion reactions involve burning substances in the presence of oxygen to produce heat and products like gases. However, the formation of carbon monoxide occurs under specific conditions that differ from typical complete combustion:

• In complete combustion, carbon or hydrocarbon fuels burn in excess oxygen to produce carbon dioxide \(( \mathrm{CO}_2 )\), water, and energy.
• However, when there is a limited supply of oxygen—a condition known as incomplete combustion—carbon monoxide \(( \mathrm{CO} )\) can form instead of carbon dioxide.
• For example, when a fire smolders or when engines don't have enough oxygen, CO can be a major byproduct because the environment does not support full conversion to \( \mathrm{CO}_2 \).

This understanding highlights the importance of well-designed combustion systems and proper ventilation to minimize CO production and exposure risks.

Properties of Gases

Carbon monoxide shares many general properties with other gases, but it presents unique challenges due to its specific attributes:

• As a colorless and odorless gas, CO is undetectable by human senses, which can make accidental exposure particularly hazardous.
• It is slightly lighter than air, meaning it can mix quickly and efficiently throughout the surrounding atmosphere.
• Its reactivity makes it a useful industrial gas, especially in synthesis reactions like methanol production.
• Despite being toxic, CO’s properties enable numerous controlled industrial processes, making understanding its behavior critical for industry professionals.

When dealing with CO or similar gases, awareness and proper detection methods are fundamental to ensure safety and prevent potential health risks.