Question

In 1984, the Bhopal gas tragedy took place because methyl isocyanate
a. Reacted with $CO_2$
b. Reacted with water
c. Reacted with DDT
d. Reacted with ammonia

Answer 1

Hint: Methyl isocyanate is an organic compound used in making carbamate pesticide which reacts exothermically with water to produce carbon dioxide, methylamine, dimethylurea and/or trimethyl biuret. Reaction is relatively slow below 20°C but becomes violent at more elevated temperatures or in the presence of acids and bases release of isocyanate vapours due to release of heat of reaction (exothermic).

Complete answer:
On the night of December 2, 1984, chemical, methyl isocyanate (MIC) spilt out from Union Carbide India Ltd’s (UCIL’s) pesticide factory turned the town of Bhopal into a huge death chamber . it had been India’s first major industrial disaster. A minimum of 30 tonnes of methyl isocyanate gas killed quite 15,000 people and affected over 600,000 workers. The Bhopal gas tragedy is understood as the world's worst industrial disaster.

According to reports, by December 2 eve, water had entered the malfunctioning tank, which resulted in a runaway reaction . The pressure within the tank increased five times by night. By midnight, the workers within the MIC area started feeling the consequences of MIC gas. The choice to deal with the leak was to be made a few minutes later. However, by then the reaction within the tank had reached a critical state. About 30 tonnes of MIC escaped from the tank into the atmosphere within an hour. Most Bhopal residents were made conscious of the gas leak by exposure to the gas itself.

Hence, the correct answer is option (B).

Note: MIC (methyl isocyanate) is a volatile, colorless liquid that is extremely flammable, and potentially explosive when mixed with air. MIC reacts with water, giving off heat and producing methylamine and carbon dioxide. The liquid and vapor are toxic when inhaled, ingested, or exposed to the eyes or skin.