Quote from: Siba on December 07, 2025, 05:40:37 PMThe 4 questions are about titrations
Here question 1 and 2
 

Vinegar is acetic acid and they reactin 1:1 molar ratio.
HC₂H₃O₂ (aq) + NaOH ---> NaC₂H₃O₂+ H2O
Planning
M*V (L) moles of NaOH --> Moles of HC₂H₃O₂-->divide by volume of vinegar (0.010L) Molarity of HC₂H₃O₂

Density = mass /Volume
get the mass of 10 mL of vinegar solution
convert the moles HC₂H₃O₂ into grams
Mass% = mass of HC₂H₃O₂ *100%/mass of vinegar solution

For first question
You calculate H+ ions moles from given information
Moles of HCl = M* V (L) = moles of H⁺
Moles of HNO₃ = M* V (L) = moles of H⁺
Add them  moles of H⁺ = 0.0300 moles
Similarly calculate moles from all bases.
Moles of RbOH = M*V(L)= moles OH ^-
Moles Ca(OH)2 = M*V (L) and double of this is equal to OH ^- moles
Add moles of OH^- from both bases = .0447 moles
Now H⁺ + OH^- --> H₂O
1:1 molar ratio
Now we can see OH- is more than H+
So solution is basic
Excess of OH- = .0447-.0300= .0147 moles
[OH-] = total moles left / total volume in L

The 4 questions are about titrations
Here question 1 and 2
 

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Starting material has two carbons in the side chain (outside the aromatic ring), while the final product has four carbons. So we need to introduce two extra carbons. The best way is to use an acetylide ion, which can undergo an SN2 reaction with a primary alkyl halide.
First, we must create a good leaving group on the starting hydrocarbon:


Carry out free-radical bromination (Br₂, hν). This introduces Br on the more substituted (secondary) benzylic carbon.


Convert this secondary bromide to a primary bromide. Do this by:


E2 elimination to form the alkene, then


anti-Markovnikov addition of HBr (HBr, ROOR) to place Br on the terminal (primary) carbon.




Now we have a primary alkyl bromide:


Treat with an acetylide ion (e.g. Na⁺ −C≡CH). The acetylide does an SN2 attack on the primary bromide, adding two carbons and giving a terminal alkyne.


Finally, perform hydration of the alkyne (H₂O, H₂SO₄, HgSO₄). This gives the ketone after keto–enol tautomerism, which is the desired product.

Kindly help with this one.

nvm I understood, you can find ksp of insoluble compounds using dissociation equation

How do you find the Ksp of an extremely insoluble compound? Like for a soluble compound you would write the dissociation equation and use the molar solubility provided & the ratios in the balanced equation to calculate Ksp, but for an insoluble compound is it still accurate to write the dissociation equation and calculate it from there, if it's barely going to dissociate? I don't remember if we covered this in class, and I searched up the definiton of Ksp, and it said it calculates the solubility of a "sparingly soluble compound," is that true?

Quote from: amimi on November 08, 2025, 07:31:55 PMThank you! So for those four structures I incorrectly said were racemic, I would circle no instead and place everything on lines instead of wedges or dashes?

Yes

Thank you! So for those four structures I incorrectly said were racemic, I would circle no instead and place everything on lines instead of wedges or dashes?