In a school practical, 2 cm3 of 2.0M hydrogen peroxide is added to 2 cm3 of an active (unboiled) yeast suspension in a test tube, and a glowing splint is immediately inserted into the tube above the mixture. What happens to the glowing splint?
Model answer
it relights
Also accepted: relights, it glows brighter
Explanation
Active yeast contains the enzyme catalase, which rapidly breaks down hydrogen peroxide into water and oxygen. The oxygen released relights a glowing splint, the standard test for oxygen gas.
Derived from ZIMSEC Biology Paper 4 (Practical Test), Jun 2004, Q1