General Chemistry Examination Questions

Hi Haizo, let's work through this set of chemistry questions together, focusing on laboratory safety, gas tests, Organic chemistry, and concentration units.

Starting with disposal of laboratory wastes. It is crucial to manage these correctly to prevent environmental damage and safety hazards.

Two common methods are incineration, which involves burning waste at high temperatures, and chemical neutralization, where hazardous acids or bases are treated to be safely disposed of down the drain.

Next, let's describe how to test for hydrogen gas. Note that the question mentions hydrogen can be tested in solution, which typically refers to observing gas evolved from a reaction mixture.

To test for hydrogen, you insert a burning splint into the mouth of the test tube containing the gas. If hydrogen is present, it will burn with a characteristic 'pop' sound.

Moving on to alkanals, which are more commonly known as aldehydes. We need to describe two of their chemical properties.

First, alkanals are easily oxidized to carboxylic acids. For example, using acidified potassium dichromate will turn the solution from orange to green as the aldehyde is oxidized.