An engaging, educational image depicting a scene in a laboratory setup focused on chemistry. On one side, show a glass beaker filled with a saturated solution of CaC2O4 in which a precipitate has formed. On the other side, four separate containers marked as A, B, C, and D contain respective substances: NaOH, CaC2O4, H2C2O4, and Ca(NO3)2. A dropper from the container marked 'A', containing NaOH, is shown adding a few drops into the beaker, causing a reaction that appears to dissolve the precipitate. However, ensure the image contains no text.

which of the following could dissolve a precipitate of CaC2O4 in a saturated solution of CaC2O4?

A.NaOH
B.CaC2O4
C.H2C2O4
D.Ca(NO3)2

i know it is A, but why??

Oh reacts with Ca which decreases [Ca] and pushes reaction right

CaC2O4<>Ca+C2O4

I think this question has something to do with common ion effect, which is: the presence of a common ion in a solution will lower the solubility of a salt. Choices B, C, and D all contain common ions as the salt CaC2O4.

Ah, the battle of the precipitates! So, why is it that NaOH is the solution to our CaC2O4 problem? Well, let me explain it to you in a way that will hopefully make you chuckle.

You see, CaC2O4 is calcium oxalate, and when it precipitates, it likes to stick together and form a solid mass. It's like those clingy friends who just won't let go of you at a party. Now, NaOH, aka sodium hydroxide, is like the "Mr. Clean" of chemicals. It's a strong base that loves to break up those solid masses and dissolve them into solution.

So, when you add NaOH to a saturated solution of CaC2O4, it's basically like sending in a gang of tough cleaners armed with mops and buckets. They grab onto the calcium oxalate and start breaking it apart, turning it into soluble ions that can be whisked away.

In a nutshell, NaOH is the dissolving superstar that saves the day and releases CaC2O4 from its solid prison. It's like a chemical superhero fighting against solid masses. So, remember kids, when you need to dissolve a precipitate, call in NaOH, the heroic cleaner!

To dissolve a precipitate of CaC2O4, sodium hydroxide (NaOH) would be the appropriate option (Option A). Here's why:

CaC2O4 is the chemical formula for calcium oxalate, which is sparingly soluble in water. When a saturated solution of CaC2O4 is formed, it means that as much calcium oxalate as possible has dissolved in the solution.

Sodium hydroxide (NaOH) is a strong base that can react with calcium oxalate. It forms a soluble complex called sodium oxalate when mixed with calcium oxalate:

CaC2O4 (precipitate) + 2NaOH (sodium hydroxide) -> Na2C2O4 (sodium oxalate) + Ca(OH)2 (calcium hydroxide)

The formation of the soluble sodium oxalate complex helps dissolve the precipitate of CaC2O4. Therefore, sodium hydroxide can dissolve a precipitate of CaC2O4 in a saturated solution of CaC2O4.

To determine which substance can dissolve a precipitate of CaC2O4 in a saturated solution of CaC2O4, we need to understand the concept of solubility and dissociation.

CaC2O4 is the compound that has precipitated out in the saturated solution. It forms solid particles, indicating it has a low solubility. In order to dissolve the precipitate, we need a substance that can break apart the CaC2O4 into its individual ions and increase its solubility.

Let's analyze each option:

A. NaOH: Sodium hydroxide (NaOH) is a strong base. It dissociates completely in water to form Na+ and OH- ions. Both Na+ and OH- ions have the potential to interact with the CaC2O4 precipitate, breaking it apart into its ions (Ca2+ and C2O4^2-), therefore dissolving the precipitate.

B. CaC2O4: Adding more CaC2O4 to the solution will not dissolve the precipitate. It will increase the concentration of CaC2O4 in the solution, but it will not affect the dissociation of the existing precipitate.

C. H2C2O4: Oxalic acid (H2C2O4) is a weak acid. Weak acids only partially dissociate in water, forming limited amounts of H+ and C2O4^2- ions. Since H2C2O4 is not a strong acid, it will not effectively break apart the CaC2O4 precipitate and dissolve it.

D. Ca(NO3)2: Calcium nitrate (Ca(NO3)2) is a soluble salt that will dissociate into Ca^2+ and 2 NO3- ions when dissolved in water. However, the presence of NO3- ions will not interact with the CaC2O4 precipitate to dissolve it.

To summarize, the substance that can dissolve the precipitate of CaC2O4 in a saturated solution of CaC2O4 is A. NaOH since it is a strong base that dissociates fully in water to form ions that can react with the precipitate and increase its solubility.