In food technology, which gas is commonly used for the artificial ripening of harvested green fruits such as bananas and mangoes?

Introduction / Context:
This general chemistry and biology question deals with post harvest food technology. It asks which gas is used for the artificial ripening of green fruits. Understanding this concept is important for agriculture, storage, transport and the food industry because ripening control affects both quality and marketability of fruits.

Given Data / Assumptions:

• The context is artificial ripening of green fruits such as bananas, mangoes and tomatoes.
• Options list several substances: acetone, carbon dioxide, ethylene, ethyl alcohol and ammonia.
• We are looking specifically for a gas that can trigger and regulate ripening.
• We assume modern, safer technology rather than outdated chemical practices.

Concept / Approach:
Ripening of many climacteric fruits is controlled by plant hormones, among which ethylene is the most important natural ripening hormone. Ethylene is a simple hydrocarbon gas (C2H4) produced by plants. In post harvest technology, controlled exposure of fruits to small amounts of ethylene accelerates ripening in a uniform and predictable manner. While some older practices used calcium carbide, which generates acetylene gas, modern recommended practice is to use ethylene itself because it is safer and more closely mimics natural processes.

Step-by-Step Solution:
1) Identify which listed substances are gases under ordinary conditions and known to influence plant processes.2) Ethylene (C2H4) is a gaseous plant hormone that promotes ripening, flower opening and leaf abscission.3) In artificial ripening chambers, fruits are exposed to controlled concentrations of ethylene to trigger and speed up the natural ripening process.4) Acetone and ethyl alcohol are liquids used as solvents and antiseptics, not standard ripening agents.5) Carbon dioxide and ammonia are industrial gases but do not function as primary ripening hormones for fruit; high carbon dioxide levels can even slow respiration.6) Therefore, the correct gas used for artificial ripening of green fruits is ethylene.

Verification / Alternative check:
Horticulture and food science materials describe ripening facilities where ethylene generators or cylinders maintain ethylene levels around a few parts per million to ripen bananas and other fruits in storage rooms. The process is carefully monitored to avoid over ripening. Regulatory bodies in many countries discourage or restrict the use of calcium carbide because of health hazards, further encouraging direct use of ethylene gas for controlled ripening. This confirms ethylene as the correct answer.

Why Other Options Are Wrong:
Acetone: An organic solvent used in laboratories and industry; it is not a ripening hormone for fruits.
Carbon dioxide: Plays roles in respiration and atmosphere control but is not the primary ripening gas; high levels can even suppress ripening.
Ethyl alcohol: Used as a disinfectant and solvent; it does not function as a standard ripening gas in post harvest technology.
Ammonia: A pungent gas used in fertilisers and cleaning agents, not suitable or safe as a ripening hormone.

Common Pitfalls:
Some students confuse ethylene with acetylene because of the use of calcium carbide in older ripening practices. Calcium carbide reacts with water to release acetylene, which can have ripening like effects but poses health risks due to impurities. Modern exam questions typically expect the scientifically correct answer, ethylene, which is the natural plant hormone. Remember that ethylene is the key plant hormone for ripening, and its name appears in many plant physiology topics and competitive exam questions.

Final Answer:
The gas commonly used for the artificial ripening of green fruits is ethylene.