In environmental chemistry, which of the following toxic gases was released during the Bhopal gas tragedy of 1984 in India?

Introduction / Context:
This question refers to one of the worst industrial disasters in history, the Bhopal gas tragedy in India. General science and environmental studies courses often include this incident as an example of the dangers of industrial toxic chemicals. Knowing the name of the main gas involved is part of basic environmental awareness and general knowledge.

Given Data / Assumptions:

• The event is the Bhopal gas tragedy.
• We are asked which gas was released during this disaster.
• Options mention different isocyanate related compounds and other gases.

Concept / Approach:
The Bhopal gas tragedy involved the accidental release of a highly toxic gas called methyl isocyanate. It was stored at a pesticide plant and leaked into the surrounding area, causing thousands of deaths and long term health effects. The other similar sounding names in the options can cause confusion, but methyl isocyanate is the correct chemical identity of the gas involved in this incident.

Step-by-Step Solution:

Verification / Alternative check:
Reports, documentaries and textbooks that describe the Bhopal disaster consistently name methyl isocyanate as the toxic gas released. It is often abbreviated as MIC in the literature. The incident is used in case studies of industrial safety and environmental law, and every reliable source repeats this same chemical name for the gas. Other isothiocyanates do not appear in those accounts as the main released gas, confirming that methyl isocyanate is the correct choice.

Why Other Options Are Wrong:

• Sodium isothiocyanate: This is an entirely different chemical compound and was not the primary gas released in Bhopal.
• Nitrogen isothiocyanate: This is not the gas associated with the tragedy.
• Potassium isothiocyanate: Again, not the compound linked to the Bhopal disaster.
• Carbon monoxide: A common toxic gas, but not the one historically connected with the Bhopal gas tragedy.

Common Pitfalls:
The main pitfall in this question is confusion due to similar sounding chemical names that include cyanate or isothiocyanate. Some learners may also mistakenly recall other famous gas incidents and mix up their details. Focusing on the specific historical association of Bhopal with methyl isocyanate and remembering the abbreviation MIC can help fix the correct answer in memory for exams and general awareness quizzes.

Final Answer:
The toxic gas released during the Bhopal gas tragedy was Methyl isocyanate.