$1.$ Indicate the strongest non$-$covalent interaction for each individual compound. $($London dispersion, dipole$-$dipole, hydrogen bonding$)$

$2.$ Rank the following compounds from most soluble to least soluble in water

a$.$ Phenol

b$.$ Benzene

c$.$ Cyclohexane

d$.$ Sodium phenolate

$3.$ You synthesized benzyl alcohol via the reduction of benzoic acid. Unfortunately, there is still benzoic acid shown in the NMR which is an impurity. How would you purify this using extraction?

$4.$ You synthesized cinnamic acid using the following reaction

The conditions were chosen in such a way that the malonic acid $($starting material$)$ was limiting and benzaldehyde was in excess. During the workup $($extraction$)$ the following steps were done.

The reaction mixture was in ethyl acetate

It was washed with $1\mathrm{.}0$ M HCl $(3$x$)$

It was extracted with NaHCO$3(3$x$)$

The NaHCO$3$ was acidified to pH $1$ and extracted with ethyl acetate $(3$x$)$

The ethyl acetate $($from previous step$)$ was washed with brine $(1$x$)$

The ethyl acetate was dried over MgSO$4,$ filtered and evaporated

Explain each step and discuss which compound is in which layer per step.

$5.$ Describe the difference between the following a$.$ Precipitation

b$.$ Crystallization c$.$ Trituration

$6.$ When performing a recrystallization and the solids do not fully dissolve, what is a possible explanation, explain why.

a$.$ Wrong choice of solvent

b$.$ Too little amount of solvent

c$.$ Solid is an impurity

d$.$ All of the above

$7.$ You check your reaction and see $3$ different spots on your TLC $($Sillica based$).$ Assume you have the following compounds in your reaction mixture, which spot is $1,2,$ and $3($in order of top to bottom$)?$ You can ignore the eluent in this question

A: benzoic acid, benzyl alcohol, benzyl benzoate

B: cyclohexanone, cyclohexanol, cyclohexane

$8.$ Assume the following TLC$$s:

You run a TLC of your reaction mixture

a$.$ But all the spots are on the baseline, should the eluent be more or less polar?

b$.$ but all the spots are on the top of your TLC$,$ should the eluent be more or less polar

c$.$ and your reaction mixture shows two spots. Is the reaction cleanly converted?

d$.$ On which the starting materials are at Rf $0\mathrm{.}15$ and $0\mathrm{.}3.$ Your product shows two spots

one at $0\mathrm{.}3$ and one at $0\mathrm{.}4.$ Is the reaction complete?

$9.$ Using a $2$ mm cell, a calibration curve for Br$2$ in carbon tetrachloride is made. Find the molar absorption coefficient at the wavelength employed.

$[$Br$2]($mol$/$L$)0\mathrm{.}00100\mathrm{.}00500\mathrm{.}01000\mathrm{.}0500$ T $($percent$)81\mathrm{.}435\mathrm{.}612\mathrm{.}70\mathrm{.}00030$

$10.$ Below you see three forms of the pH indicator phenolphthalein. Can you identify which ones are colorless and which one gives a pink color?

Can you also identify which structure corresponds to which pH range? Below $8\mathrm{.}2,10-12\mathrm{.}5$ and above $12\mathrm{.}5$

$11.$ The compound below has $4$ signals. Can you indicate the type of splitting $($singlet$,$ doublet, triplet etc.$)$ for each of the signals?

$12.$ You are doing the following reaction but are unsure of what the resulting compound should be$.$ Can you use $1$H$-$NMR to see which compound you have made? Describe the differences in the spectra of the two possible products.