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3 years ago

Propose a mechanism for the following reaction.

Chemistry

1 answer:

raketka [301]3 years ago

5 0

First, recognize that this is an elimination reaction in which hydroxide must leave and a double bond must form in its place. It is likely an E2 reaction. Here is an efficient mechanism:
1) Pre-reaction: Protonate the -OH to make it a good leaving group, water. H2SO4 or any strong H+ donor works. The water is positively charged but still connected to the compound.
2) E2: Use a sterically hindered base, such as tert-butoxide (tButO-) to abstract the hydrogen from the secondary carbon. [You want a sterically hindered base because a strong, non-sterically hindered base could also abstract a hydrogen from one of the two methyl groups on the tertiary carbon, and that leads to unwanted products, which is not efficient]. As the proton of hydrogen is abstracted, water leaves at the same time, creating an intermediate tertiary carbocation, and the 2 electrons in the C-H bond immediately are used to make a double bond towards the partial positive charge.
In the products we see the major product and water, as expected. Even though you have an intermediate, remember that an E2 mechanism technically happens in one step after -OH protonation.

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Mixtures of benzene and cyclohexane exhibit ideal behavior. A solution was created containing 1.5 moles of liquid benzene and 2.

goblinko [34]

Answer:

Vapour pressure of cyclohexane at 50°C is 490torr

Vapour pressure of benzene at 50°C is 90torr

Explanation:

Using Raoult's law, pressure of a solution is defined by the sum of the product sbetween mole fraction of both solvents and pressure of pure solvents.

$P_{solution} = X_{A}P^0_{A}+X_{B}P^0_{B}$

In the first solution:

$X_{cyclohexane}=\frac{2.5mol}{2.5mol+1.5mol} =0.625$

$X_{benzene}=\frac{1.5mol}{2.5mol+1.5mol} =0.375$

$340torr = 0.625P^0_{A}+0.375P^0_{B}$ (1)

For the second equation:

$X_{cyclohexane}=\frac{3.5mol}{3.5mol+1.5mol} =0.700$

$X_{benzene}=\frac{1.5mol}{3.5mol+1.5mol} =0.300$

$370torr = 0.700P^0_{A}+0.300P^0_{B}$ (2)

Replacing (2) in (1):

$340torr = 0.625P^0_{A}+0.375(1233.3-2.333P^0_{A})$

$340torr = 0.625P^0_{A}+462.5-0.875P^0_{A}$

-122.5torr = -0.250P°A

$P^0_{A} = 490 torr$

Vapour pressure of cyclohexane at 50°C is 490torr

And for benzene:

$370torr = 0.700*490torr+0.300P^0_{B}$

$P^0_{B}=90torr$

Vapour pressure of benzene at 50°C is 90torr

3 0

2 years ago

Science 7 Grade 7. Can anyone please help me answer these science questions?

masha68 [24]

A cellphone battery is a electrical energy
and a piston in an engine is an thermal energy

6 0

2 years ago

Read 2 more answers

Salt is often added to water to raise the boiling point to heat food more quickly. if you add 30.0g of salt to 3.75kg of water,

sammy [17]

Assuming an ebullioscopic constant of 0.512 °C/m for the water, If you add 30.0g of salt to 3.75kg of water, the boiling-point elevation will be 0.140 °C and the boiling-point of the solution will be 100.14 °C.

<h3>What is the boiling-point elevation?</h3>

Boiling-point elevation describes the phenomenon that the boiling point of a liquid will be higher when another compound is added, meaning that a solution has a higher boiling point than a pure solvent.

Step 1: Calculate the molality of the solution.

We will use the definition of molality.

b = mass solute / molar mass solute × kg solvent

b = 30.0 g / (58.44 g/mol) × 3.75 kg = 0.137 m

Step 2: Calculate the boiling-point elevation.

We will use the following expression.

ΔT = Kb × m × i

ΔT = 0.512 °C/m × 0.137 m × 2 = 0.140 °C

where

ΔT is the boiling-point elevation
Kb is the ebullioscopic constant.
b is the molality.
i is the Van't Hoff factor (i = 2 for NaCl).

The normal boiling-point for water is 100 °C. The boiling-point of the solution will be:

100 °C + 0.140 °C = 100.14 °C

Learn more about boiling-point elevation here: brainly.com/question/4206205

7 0

2 years ago

The document that provides the structure for the us government is

Komok [63]

The Constitution provides the basic structure for US Government.

As a sidenote, you posted this in Chemistry, when it actually belongs in another topic. Please be sure to post questions only where they belong. Thanks! :)

7 0

3 years ago

Which of the following chemical formula show an iconic compound

BaLLatris [955]

This question comes with this list of answer choices:

A. CO₂

B.N₂O

C.NaCl

 D.C₆H₁₂O₆


Answer: option C.NaCl

Justification.

1) When two diferent elements join together chemically they can form either a covalent bond or a ionic bond.

2) When the bonds are covalents the compound is called covalent, when the bonds are ionics the compound is called ionic.

3) To predict whether the compound is ionic or covalent, you must see the electronegativities of the elements.

4) Ionic compounds require the formation of ions, a posititve ion and a negative ion. The positive ion is formed when the element loses one or more electrons. The negative ion is formed when the element gains one or more electrons.

Then, in the formation of a ionic compound it is implicit the exchange of electrons (one element gains the electrons that the other lose) and this is possible, when the difference in electronegativities are high enough.

5) So, you must look at the electronegativities to make your prediction. In the given options, the compounds of the options A, B and D are between non-metals. Then, you can predict that their electronegativities are not as much differet as to form ions. They will form covalent bonds.

6) Being sodium and chloride a metal and non-metal, you can expect that their electronegativities differ quite enough to form the ionic bond (this is not true for any pair of non-metal and metal elements, but being them the only pair of metal - non metal elements, this is the only option).

This leads to the conclusion that the NaCl formula shows an ionic compound, and is the answer.

5 0

3 years ago