What type of gas can some reactive materials produce violently when in contact with water?

The type of gas that some reactive materials produce violently when they come into contact with water is hydrogen. Certain metals, especially alkali metals like sodium and potassium, react with water in a vigorous manner, producing hydrogen gas and often leading to explosive situations. This reaction can create flammable hydrogen gas that poses significant safety hazards in an electrical environment or any situation where sparks are present.

Understanding the behavior of reactive materials with water is crucial for ensuring safety, as these reactions can lead to not just the release of gases, but also significant heat and pressure that can result in explosions. It is important to recognize not only the gases produced but also the conditions under which these violent reactions can occur. In contrast, while poisonous gases can be a concern, they are not specifically linked to reactions with water in the same explosive manner as hydrogen.