I have no idea how to approach this problem. Given sodium hydroxide, sulfuric acid, sodium silicate and magnesium hydroxide, which has low solubility? Please help, I'm reviewing for a test.
I have no idea what you mean. Magnesium hydroxide is not soluble in water, but in acids, it reacts.
You should know or learn the solubility rules. Here is a very simplified version.
http://www.files.chem.vt.edu/RVGS/ACT/notes/solubility_rules.html
Thanks. Magnesium hydroxide was given as the correct answer but I don't know how you can tell (the only extra in the question was that the magnesium hydroxide was the main component of milk of magnesia). Is it because hydroxide is insoluble?
Did you go to the site I gave you for the solubilities? Probably not.
To answer you repost questin, no, not because hydroxide is insoluble. NaOH is soluble, KOH is soluble, CsOH is soluble, lots of hydroxides are soluble. However, magnesium hydroxide is insoluble (you know this by the solubility rules). The hint with the milk of magnesia: MOM consists of magnesium hydroxide. When you shake it up do you see a white suspension (yes) or a clear, colorless solutin (no).
Thanks for your help.
To determine which compound has low solubility, we can look at their respective solubility products (Ksp) values. The smaller the Ksp value, the lower the solubility.
First, let's find the Ksp values for the given compounds:
1. Sodium hydroxide (NaOH)
- NaOH dissolves completely in water, so its Ksp value is extremely high, indicating high solubility.
2. Sulfuric acid (H2SO4)
- Sulfuric acid is a strong acid that ionizes completely in water, so it does not have a Ksp value.
3. Sodium silicate (Na2SiO3)
- Sodium silicate is a complex compound and does not have a Ksp value.
4. Magnesium hydroxide (Mg(OH)2)
- To find the Ksp, we need to write the balanced chemical equation for the dissolution of magnesium hydroxide in water:
Mg(OH)2(s) ⇌ Mg2+(aq) + 2OH-(aq)
- The Ksp expression for magnesium hydroxide is:
Ksp = [Mg2+][OH-]^2
- According to solubility data, magnesium hydroxide has a Ksp value of approximately 1.8 x 10^-11, which is very small. Therefore, magnesium hydroxide has low solubility.
Based on the Ksp values, we can conclude that magnesium hydroxide has the lowest solubility among the given compounds.