Official OAT sample exam question

[euphaire]

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Hi everyone,
I'm sure most of you've tried the sample test from the official ada website. One of the questions (#61) is:
61. 0.60M solution made by dissolving solid compound X in water. After a few seconds, the concentration of X in water becomes 0.40M. All of the following could account for this EXCEPT:
A. precipitation
B. neutralization
C. evaporation
D. decomposition
E. disproportionation

I thought the answer would be E or C because E looks weird (lol) and solid dissolving in water doesn't sound like it's gonna evaporate (sorry for my poor background in science). However, the solution is A.

Why is that? *super confused*

Thank you in advance!!
Cherry

 

[weiss]

It's an error. The correct answer should be Evaporation. See this thread http://forums.studentdoctor.net/showthread.php?t=605494 for errors in the test. Hope this helps 🙂

 

[euphaire]

Thank you so much! Wow I can't believe the sample test has so many errors. This is pure evil. But your link is a life saver 🙂