Passage VII
Bacteria, fungi, and viruses (microorganisms) cause diseases and infections. Disinfectants are chemical agents used on inanimate objects to kill or inhibit the growth of microorganisms. Antiseptics are chemical agents used on the skin to kill or inhibit the growth of microorganisms. Several groups of disinfectants and antiseptics are depicted in Table 1.
The chemical agents that make up disinfectants and antiseptics can be dissolved either in alcohol (forming a tincture) or water (forming an aqueous solution). The effectiveness of a variety of antiseptics against the normal microbial flora of the skin is shown in Figure 1.
40. According to Figure 1, if a researcher prepared a disinfectant solution of 60% alcohol, the time of exposure required to kill 90% of the bacteria present would be:
Your Answer is
Correct Answer is J
Explanation
Look at the 70% ethanol line segment in figure 1, when the ordinate bacteria surviving is 10% (kill 90% of the bacteria), the abscissa time is 120 sec;
60% alcohol The sterilization ability should be weaker, so it takes longer than 120 sec