<p>Need help with this from the BB</p>
<p>Na2CrO4, soluble yellow solid
PbCrO4, insoluble yellow solid
NaNO3, soluble white solid
Pb(NO3)2, soluble white solid</p>
<p>A - Yellow solid and colorless solution
B - Yellow solid and yellow solution
C - White solid and colorless solution
D - No solid and yellow solution
E - No solid and colorless solution</p>
<p>Observed when 1 mol of Na2CrO4 and 2 mol of Pb(NO3)2 are mixed with 1 L of water.</p>
<p>The answer is A. I pretty much have no idea why it is the answer, so can someone PLEASE explain this to me? (Please be thorough!)</p>
<p>When you add water, you basically make these into aqueous solutions. The double replacement reaction is:</p>
<p>Na2CrO4(aq) + Pb(NO3)2(aq) -> PbCrO4(s) + 2NaNO3(aq)</p>
<p>The PbCrO4 is a yellow solid that precipitates. The sodium nitrate salt is soluble and dissociates in aqueous solution, which is colorless (adding salt to water = colorless, and nitrate is colorless too (99% sure))</p>
<p>I believe the amounts (mols, liters) are just there to confuse you.</p>
<p>Sodium Chromate + Lead Nitrate = Sodium Nitrate + Lead Chromate</p>
<p>NaNO3 + PbCrO4
You get soluble white solid and insoluble yellow solid.</p>
<p>Thus yellow solid and white solution. [A]</p>
<p>The amount of moles actually seems to be affecting the answer.</p>
<p>Here is another part to the problem:</p>
<p>Observed when 3 mol of Na2CrO4 and 1 mol of Pb(NO3)2 are mixed with 1 L of water.</p>
<p>The answer is B… explain pleaseeeeee</p>
<p>My guess is that the reaction goes to completion, and there is a lot of leftover Na2CrO4 which affects the color.</p>