Copper (II)oxide was heated in the apparatus shown below and dry ammonia was passed over it. After a few seconds, the test tube was placed in position and a gas collected. The gas collected was:

Biochemical Engineering mainly deals with the design, construction, and advancement of unit processes that involve biological organisms (such as fermentation) or organic molecules (often enzymes) and has various applications in areas of interest such as biofuels, food, pharmaceuticals, biotechnology, and water treatment processes. (Source: Wikipedia)