Question

Yeah, I need help :(

A student is deciding which chemicals are acids by measuring their pH. He sees that a solution of CO2 has an acidic pH. He decides that he must have contaminated his sample. He thinks that CO2 could not create hydrogen ions in the solution since it contains no hydrogen atoms. Explain what is incorrect about the student’s reasoning.

Answer 1

The student is worng, because CO₂ is acidic oxide. When an acidic oxide reacts with water, acid is formed. In the student's case, the following reaction happens:

H₂O + CO₂ ⇒ H₂CO₃

The H₂CO₃ is carbonic acid and it is the scoure of the H⁺ atoms. The sample is not contaminated.