<p>I am currently using CB's SAT II: Subject Tests (2ed). On page 300, there is a question involving a series of reactions with some missing pieces of information: </p>
<p>The answer choices:</p>
<p>(A) Cr2O7<a href="B">2-</a> H<a href="C">1+</a> OH <a href="D">1-</a> Cr<a href="E">3+</a> Ba[2+]</p>
<p>"Which of the above is the appropriate ion for each blank in the following series of reactions?"</p>
<p>OH[1-] + <em>(5)</em> ---> CrO4[2-] + H[1+] -<em>(6)</em>--> BaCrO4(s) <--(8),(7)--> Ba[2+] + Cr2O7[2-] + H2O --SO2(g),H+--> BaSO4(s) + <em>(9)</em> + H2O</p>
<p>I'm sorry if this is hard to read. (n) is the number of the question and the species between the arrows go either above or below the arrow (LIKE a catalyst or hydrolysis rxn) - #8 is below the arrow and, I assume, applies to the reverse reaction.</p>
<p>Here are the solutions:</p>
<p>5 - A
6 - E
7 - B
8 - C
9 - D</p>
<p>If someone can explain why these are the answers, I would greatly appreciate it.</p>
<p>Thanks, a lot.</p>