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3 years ago

What reaction conditions most effectively convert a carboxylic acid to a methyl ester

Chemistry

2 answers:

ycow [4]3 years ago

4 0

Answer:

Fischer Esterification

Explanation:

Fischer esterification or Fischer-Speier esterification is a carboxylic esterification reaction that uses an inorganic acid as a catalyst, mainly sulfuric acid (H2SO4).

The carboxylic acids are usually too weak acids, so they have little tendency to yield the proton (H +) that they lose in the esterification.

A stronger acid, such as sulfuric acid, behaves like a proton donor and facilitates the esterification reaction.

First, sulfuric acid injects a proton into the carboxyl group

The alcohol molecule, R’-OH, has an electron-rich oxygen atom, is attracted to the protonated carboxylic structure

This complex is not very stable and stabilizes towards the most favorable energy molecule, which is the ester, releasing a water molecule and a proton (H +). The proton is then used to regenerate sulfuric acid

dem82 [27]3 years ago

4 0

Answer: The convenient and efficient sonochemical method for methyl esterification of carboxylic acids reaction conditions are ;

• catalyzation by polymer-supported triphenylphosphine (0.1 eq. PS-PPh3)

• in the presence of 2,4,6-trichloro-1,3,5-triazine (1.0 eq. TCT) and Na2CO3 (2.0 eq. )

• Temperature 50°C for 10 - 30 mins

Explanation:

Methyl esters of various carboxylic acids bearing reactive hydroxyl groups as well as acid- or base-labile functionalities could be rapidly prepared within short times in good to excellent yields in high purities without column chromatography.

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1) A common experiment to determine the relative reactivity of metallic elements is to place a pure sample of one metal into an

Annette [7]

Answer: $Zn(s)+CuSO_4(aq)\rightarrow ZnSO_4+Cu$

Explanation:-

Single replacement reaction is a chemical reaction in which more reactive element displaces the less reactive element from its salt solution.

As zinc is more reactive than copper, it could easily displace copper from its aqueous solution and thus leads to formation of zinc (II) sulfate and pure copper.

The chemical reaction can be represented as :

$Zn(s)+CuSO_4(aq)\rightarrow ZnSO_4+Cu$

The phases are represented as (s) for solid sate, (l) for liquid state, (g) for gaseous state and (aq) for aqueous state.

7 0

3 years ago

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Silver occurs in trace amounts in some ores of lead, and lead can displace silver from solution: Pb(s) + 2Ag+ (aq) LaTeX: \longr

VikaD [51]

Answer : The value of $\Delta G^o$ and K is, -180 kJ/mol and $3.6\times 10^{31}$

Explanation :

The balanced cell reaction will be,

$Pb(s)+2Ag^+(aq)\rightarrow Pb^{2+}(aq)+2Ag(g)$

The half-cell reactions are:

Oxidation reaction (anode) : $Pb(s)\rightarrow Pb^{2+}(aq)+2e^-$

Reduction reaction (cathode) : $2Ag^+(aq)+2e^-\rightarrow 2Ag(g)$

Relationship between standard Gibbs free energy and standard electrode potential follows:

$\Delta G^o=-nFE^o_{cell}$

where,

$\Delta G^o$ = standard Gibbs free energy

F = Faraday constant = 96500 C

n = number of electrons in oxidation-reduction reaction = 2

$E^o_{cell}$ = standard electrode potential of the cell = 0.93 V

Now put all the given values in the above formula, we get:

$\Delta G^o=-2\times 96500\times 0.93$

$\Delta G^o=-179490J/mol=-179.49kJ/mol\approx -180kJ/mol$

Now we have to calculate the value of 'K'.

$\Delta G^o=-RT\ln K$

where,

$\Delta G_^o$ = standard Gibbs free energy = -180 kJ/mol

R = gas constant = $8.314\times 10^{-3}kJ/mole.K$

T = temperature = 298 K

K = equilibrium constant = ?

Now put all the given values in the above formula 1, we get:

$-180kJ/mol=-(8.314\times 10^{-3}kJ/mole.K)\times (298K)\times \ln K$

$K=3.6\times 10^{31}$

Therefore, the value of $\Delta G^o$ and K is, -180 kJ/mol and $3.6\times 10^{31}$

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3 years ago

2. Different versions of a gene

scoray [572]

Answer:

I believe it's A

Explanation:

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8 0

3 years ago

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The elements silicon (atomic number 14) and chlorine (atomic number 17) are both in Period 3. Which is the more reactive element

Svetlanka [38]

Answer;

-Chlorine is more reactive than silicon

Explanation;

-As you move across a period, the nuclear charge will increase; the number of energy levels will stay the same, so there is a stronger and stronger attraction for the electrons.

-The electrons are being held more tightly as you move across a period. It becomes more and more difficult to lose electrons and consequently the reactivity of non metals increases as you go from left to right across the periodic table; Therefore; chlorine is more reactive than silicon.

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3 years ago

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The fact that same molecules of matter have been around for years is supported by

Elza [17]

Answer:

The law of definite proportions

Explanation:

The law of definite proportions states that atoms combine in a molecule in a specific molar ratio or specific stoichiometry. For example, it's proved that regardless of the quantity we take, two hydrogen atoms always combine with one oxygen atom to form a water molecule.

Similarly, ionic substances follow the same pattern. Since the net charge of ionic salts should be equal to 0 and each element has a definite number of valence electrons in its shell all the time, the ions combine in a way, so that cations balance the charge of anions.

Essentially, the law of definite proportions is applicable and will be applicable in the future, since we know that each element has a fixed number of valence electrons in its ground state.

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3 years ago