CaC2 on treatment with water gives A. methane B. ethane C. ethylene D. acetylene

The correct answer is D. acetylene.

When calcium carbide (CaC2) is treated with water, it produces acetylene gas (C2H2). This reaction is known as the carbide process.

The reaction can be written as follows:

CaC2 + 2H2O → C2H2 + Ca(OH)2

The carbide process is used to produce acetylene, which is a fuel gas. Acetylene is also used in the production of other chemicals, such as vinyl chloride and acetaldehyde.

The other options are incorrect because they are not produced by the carbide process. Methane (CH4), ethane (C2H6), and ethylene (C2H4) are all hydrocarbons that are produced by other processes.

Methane is produced by