Catalase Test Questions

We did the catalse test in class and I have been able to answer some questions but not all.
Questions:
1)  Provide an example of reduction reaction performed by cells in which hydrogen is not added to the reduced compound. (I think it deals with hydrogen peroxide--> to water and oxygen)

2)  Would a flase positive due to the reaction between the loop and hydrogen peroxide be due to a lack of specificy or sensitivity of the test system?

3)  If a weakly catalase-positive organism itinitially gives a false-negative result and is not checked under the miicroscope, would the result be due to a lack of specificity or sensitivity of the test system?

4)  Why is it advisable to perform this test on a known catalase-positive organism simultaneously with the organism you are checking?

5)  What is the purpose of adding hydrogen peroxide to the uninoculated tube?