Answer:
Concentration of hydroxide-ion at equivalence point = 
Explanation:
1 mol of 
reacts with 1 mol of KOH to produce 1 mol of 
At equivalence point, all gets converted to .
Moles of produced at equivalence point is equal to moles of KOH added to reach equivalence point.
So, moles of produced = 
Total volume of solution at equivalence point = (25.00+43.76) mL = 68.76 mL
Concentration of at equivalence point = 
produced at equivalence point is due to hydrolysis of . We have to construct an ICE table to calculate concentration of at equivalence point.
I:0.0897 0 0
C: -x +x +x
E: 0.0897-x x x
![\frac{[HC_{3}H_{5}O_{2}][OH^{-}]}{[C_{3}H_{5}O_{2}^{-}]}=K_{b}(C_{3}H_{5}O_{2}^{-})=\frac{10^{-14}}{K_{a}(HC_{3}H_{5}O_{2})}](https://tex.z-dn.net/?f=%5Cfrac%7B%5BHC_%7B3%7DH_%7B5%7DO_%7B2%7D%5D%5BOH%5E%7B-%7D%5D%7D%7B%5BC_%7B3%7DH_%7B5%7DO_%7B2%7D%5E%7B-%7D%5D%7D%3DK_%7Bb%7D%28C_%7B3%7DH_%7B5%7DO_%7B2%7D%5E%7B-%7D%29%3D%5Cfrac%7B10%5E%7B-14%7D%7D%7BK_%7Ba%7D%28HC_%7B3%7DH_%7B5%7DO_%7B2%7D%29%7D)
species inside third bracket represent equilibrium concentrations
So, 
or, 
So, 
M =
So, concentration of hydroxide-ion at equivalence point = x M =
<span>B)<span>C2H6O<span>2
</span></span></span>
First, convert each percentage to grams: 38.7g, 9.70g, and 51.6g.
Next, calculate the number of moles of each element, based on the number of grams given.
C = 3.23 mol
H = 8.91 mol
O = 3.23 mol
Set up the ratio of moles of each element:
C3.34H9.70O3.23. Convert the decimals to whole numbers by dividing by the smallest subscript, 3.23.
The empirical formula is CH3O.
Now, compute the formula mass, which is 31. Finally, divide the molecular mass by the formula mass, 62/31 = 2. Multiple the subscripts by 2 to get the molecular formula.
