BR Answer reasoning

[Nymphicus]

Advertisement - Members don't see this ad

BR Gen Chem Ch5 Spoiler alert: Buffers and Titrations

I had a stylistic MCAT question:

Q: An indicator in a concentration that is too high could have what effect on a solution?

Viable Answers:
A) It could interfere with the acid/base properties of the solution being titrated
C) The color change could be too extreme to be useful

A was correct


I picked C because in the passage it stated "Indicators are used in low concentrations, so they don't become visibly detectable until at least one-tenth of the indicator is deprotonated (orange)..."

Originally I chose A but then changed to C because of the passage. Was that the wrong choice? I didn't think that I should ignore what the passage said but I don't know now that I got the wrong answer.

Any ideas?

 

[anon747]

BR Gen Chem Ch5 Spoiler alert: Buffers and Titrations

I had a stylistic MCAT question:

Q: An indicator in a concentration that is too high could have what effect on a solution?

Viable Answers:
A) It could interfere with the acid/base properties of the solution being titrated
C) The color change could be too extreme to be useful

A was correct


I picked C because in the passage it stated "Indicators are used in low concentrations, so they don't become visibly detectable until at least one-tenth of the indicator is deprotonated (orange)..."

Originally I chose A but then changed to C because of the passage. Was that the wrong choice? I didn't think that I should ignore what the passage said but I don't know now that I got the wrong answer.

Any ideas?

You may be misreading the meaning of the sentence that you quoted from the passage. It says that indicators are used in low concentrations. It then says that because they are used in low concentrations, they don't become visible until 1/10 of it has been converted. This does not mean that having a more extreme color change would be a bad thing. In fact, having a really extreme color change could be a good thing for an indicator. But the point of the questions is just that you can't put a whole ton of indicator in or it may actually interfere with the reaction you're trying to observe. So I guess you can look at it like this: the question is basically asking what is a negative consequence of putting in too much indicator. Having an extreme color change (whether or not that would actually happen) is not necessarily a negative, so you can rule that answer out.

 

[apumic]

BR Gen Chem Ch5 Spoiler alert: Buffers and Titrations

I had a stylistic MCAT question:

Q: An indicator in a concentration that is too high could have what effect on a solution?

Viable Answers:
A) It could interfere with the acid/base properties of the solution being titrated
C) The color change could be too extreme to be useful

A was correct


I picked C because in the passage it stated "Indicators are used in low concentrations, so they don't become visibly detectable until at least one-tenth of the indicator is deprotonated (orange)..."

Originally I chose A but then changed to C because of the passage. Was that the wrong choice? I didn't think that I should ignore what the passage said but I don't know now that I got the wrong answer.

Any ideas?

A little EK VR technique comes in well here. Your answer doesn't answer the question. The question was specifically asking about the effect on the solution. The color of the indicator IN solution is irrelevant (i.e., it's not what we're being asked about here). The acid/base properties of the soln, however, ARE a property of the soln which is what we are being asked about. You have to read the questions. Passages are often nothing more than a little background information. The questions will often require knowledge beyond the passage but the passages sort of allow the testers to test more than what you would have learned in (virtually) every 1st yr science course (in each subject). It allows them to sort of fill you in on things quickly but the expectation is still that you can figure things out and not that you rely entirely on the passage.

 

[YouNeverKnow22]

A little EK VR technique comes in well here. Your answer doesn't answer the question. The question was specifically asking about the effect on the solution. The color of the indicator IN solution is irrelevant (i.e., it's not what we're being asked about here). The acid/base properties of the soln, however, ARE a property of the soln which is what we are being asked about. You have to read the questions. Passages are often nothing more than a little background information. The questions will often require knowledge beyond the passage but the passages sort of allow the testers to test more than what you would have learned in (virtually) every 1st yr science course (in each subject). It allows them to sort of fill you in on things quickly but the expectation is still that you can figure things out and not that you rely entirely on the passage.

agree here, just answer the question. BR does a great way of making you realize simple testing mistakes early so you can hopefully fix the "common" errors come test time. good luck

 

[Nymphicus]

Alright, thanks guys