Multiple Choice
What volume of 0.855 M KOH solution is required to make 3.55 L of a solution with a pH of 12.4?
6. Chemical Quantities & Aqueous Reactions
Solutions
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In an experiment to test the effect of a new drug, which solution is typically used as the positive control?
A
A solution containing the new drug
B
A solution containing no active ingredients
C
A solution containing only water
D
A solution containing a known effective drug
Verified step by step guidance1
Understand the role of a positive control in an experiment: A positive control is used to ensure that the experiment setup is capable of producing a positive result. It helps validate the experimental procedure by using a substance known to produce the expected effect.
Identify the options given in the problem: The options are a solution containing the new drug, a solution containing no active ingredients, a solution containing only water, and a solution containing a known effective drug.
Evaluate each option: A solution containing the new drug is the test subject, not a control. A solution containing no active ingredients or only water would serve as a negative control, showing no effect. A solution containing a known effective drug is used as a positive control because it is expected to produce a known positive effect.
Select the correct option: Based on the evaluation, the correct positive control is a solution containing a known effective drug, as it provides a benchmark for the expected outcome.
Reflect on the importance of controls: Controls are crucial in experiments to validate results and ensure that any observed effects are due to the experimental variable, not external factors.
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