<p>hello
I was studying for upcoming Chemistry SAT test and I got stuck on one of the questions </p>
<p>The reaction of CaCO3 and HCl goes to completion
because reactions that form a precipitate go to completion</p>
<p>the first statement (says the book) is true but the second statement is false</p>
<p>I thought if a reaction forms a precipitate, it always goes to completion
like 2KI(aq) + Pb(NO3)2(aq) --> 2KNO3(aq) + PbI2(s)
which PbI2 is the solid in this reaction and it's one way reaction</p>
<p>can someone explain to me please?
thx:)</p>