B555`S CHEMISTRY HUB

I KEPt THE NAME OF THE QUESTION AS SUCH BECAUSE I WILL KEEP ON POSTING MY QUESTIONS IN THIS TAG ONLYYYYYYYY I WILL ADD NEW QUESTIONS DAILYYYYYYYYYYYY whats more than organic in chemistry.. so i will start with that

1]Convert aniline to phenyl acetic acid in NOT MORE THAN 5 steps....

2)Convert cyclopent2ene1one to cyclobutanol in NOT MORE THAN 5 steps....

3]give the steps for the mechanism for the conversion of cyclohexanone oxime in the presence of H+, heat to caprolactam

4]convert benzaldehyde to 3-phenylpropan-1-ol

5]what is fugisity

212 Answers

13
MAK ·

dats a tedious n tym consuming job aragorn... less tym is required to search in d same thread, i think...!!!

39
Dr.House ·

28 Two C4H6 isomers give the same C4H8O product from HgSO4 catalyzed hydration in aqueous acid.
However, these isomers give different C4H6Br4 products with excess bromine.
What are these isomeric hydrocarbons?
A) cyclobutene and methylenecyclopropane
B) 1,2-butadiene and 1,3-butadiene
C) 1-butyne and 2-butyne
D) 2-butyne and cyclobutene

30 Two C5H8 isomers undergo catalytic (Pt) hydrogenation to form the same C5H10 product. On ozonolysis followed by oxidative workup (H2O2), one isomer gave a C5H8O4 diacid, while the other isomer gave a C5H8O3 ketoacid.
Which of the following isomeric pairs correspond to this evidence?
A) cyclopentene and 1-pentyne
B) cyclopentene and 1-methylcyclobutene
C) 1-methylcyclobutene and 3-methylcyclobutene
D) cyclopentene and 3-methylcyclobutene

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31 Considering that the angles of a regular pentagon are 108º, why is cyclopentane not planar?
A) all the carbons are sp2 hybridized, so there is considerable angle strain.
B) The C-C bonds are formed by overlap of p-orbitals, so the 90º angle results in large angle strain.
C) The cyclic overlap of bonding orbitals results in anti-aromaticity destabilization.
D) The five C-C bonds have eclipsing strain.

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32 Which reaction conditions would best convert 3-hexyne to cis-3-hexene?
A) Pt catalyst and H2.
B) Lindlar's Pd catalyst and H2.
C) Na in liquid NH3.
D) NaNH2 in liquid NH3.

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33 Reaction of 1-hexene with NBS (N-bromosuccinimide) forms two isomeric bromohexenes, one of which is 3-bromo-1-hexene.
Which of the following is the other isomer?
A) 1-bromo-2-hexene.
B) 6-bromo-1-hexene.
C) 1-bromo-1-hexene.
D) 2-bromo-1-hexene.

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34 A C6H10 hydrocarbon forms an insoluble silver salt when treated with silver nitrate in ethanolic ammonia.
Acid catalyzed hydration with a HgSO4 catalyst generates a single C6H12O ketone, and pemanganate oxidation yields a C5H10O2 carboxylic acid
This compound is most likely which of the following?
A) cyclohexene.
B) methylenecyclopentane.
C) 1-hexyne.
D) 3-hexyne.

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35 Peroxide induced reaction of carbon tetrachloride with 1-butene produces which of the following?
A) 1,1,1,3-tetrachloropentane.
B) 1,1,1,2-tetrachloropentane.
C) 1-chloro-2-trichloromethylbutane.
D) 1,1-dichloro-2-ethylcyclopropane.

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36 Which of the following isomeric hexenes will have the smallest heat of hydrogenation?
A) 4-methyl-1-pentene.
B) (E)-4-methyl-2-pentene.
C) (Z)-4-methyl-2-pentene.
D) 2-methyl-2-pentene.

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37 A C8H14 hydrocarbon (X) is reduced by sodium in liquid ammonia to a single C8H16 product (Y).
Both of these compounds undergo hydrogenation (Pt catalyst) to give 2,5-dimethylhexane.
Ozonolysis of Y with an oxidative workup produces a single C4H8O2 carboxylic acid.
Reaction of Y with perbenzoic acid (C6H5CO3H) gives a chiral C8H14O product, but reaction with bromine gives an achiral C8H14Br2 product
What are X and Y?
A) X is 2,5-dimethyl-3-hexyne ; Y is cis-2,5-dimethyl-3-hexene.
B) X is 2,5-dimethyl-3-hexyne ; Y is trans-2,5-dimethyl-3-hexene.
C) X is 2.5-dimethyl-1,5-hexadiene ; Y is 2,5-dimethyl-3-hexyne.
D) X is 2,5-dimethyl-2,4-hexadiene ; Y is cis-2,5-dimethyl-3-hexene.

39
Dr.House ·

28 Which of the following procedures would be best for preparing isobutylisopropylamine, (CH3)2CHNHCH2CH(CH3)2?
A) (CH3)2CHBr + (CH3)2CHCH2NH2
B) (i) (CH3)2CHBr + (CH3)2CHCONHNa (ii) LiAlH4 in ether
C) (i) (CH3)2CHNH2 + (CH3)2CHCH=O (ii) H2 & Pt
D) (CH3)2CHCN + (CH3)2CHNH2

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29 What is the chief product from the Hofmann elimination of 4-methyl-2-aminopentane?
A) 4-methyl-1-pentene
B) 4-methyl-2-pentene
C) 2-methyl-1-pentene
D) 2-methyl-2-pentene

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30 Which of the following procedures would be best for preparing dimethylcyclohexylamine, C6H11N(CH3)2?
A) (i) dimethylamine + cyclohexanone (ii) NaBH3CN in methanol
B) dimethylamine + cyclohexylbromide in ether
C) cyclohexylamine + 2 CH3I in ether
D) (i) cyclohexylbromide + NaCN in methanol (ii) 2 CH3Li in THF

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31 What reagent would be best for converting the amide of (R)-2-phenylpropanoic acid, C6H5CH(CH3)CONH2, into (R)-1-amino-2-phenylpropane?
A) excess H2 & Pt.
B) NaOBr in aqueous base.
C) NaBlH4 in methanol
D) LiAlH4 in ether.

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32 What reagent would be best for converting the amide of (R)-2-phenylpropanoic acid, C6H5CH(CH3)CONH2, into (R)-1-phenylethylamine?
A) excess H2 & Pt.
B) NaOBr in aqueous base.
C) NaBlH4 in methanol
D) LiAlH4 in ether.

39
Dr.House ·

i just posted them so that u know them if u wont

thats it

39
Dr.House ·

HEY GUYS IS IT PROVING TO BE USEFUL OR NOT?

39
Dr.House ·

. Which of the following is true for 3-methylbutanal?

a) This compound may be classified as an aldehyde.
b) This compound may be classified as a ketone.
c) An aldol reaction takes place on treatment with NaOH solution.
d) There is no reaction with LiAlH4 in ether solution.
e) An excess of CH3MgBr in ether reacts to give 4-methyl-2-pentanol.
f) Wolff-Kishner reduction gives butane.
g) This compound is an isomer of 3-pentanone.

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2. Which of the following is true for 3-methyl-2-butanone?

a) It may be prepared by CrO3 oxidation of 2-methyl-2-butanol.
b) Reaction with NaBH4 gives a secondary alcohol.
c) It may be prepared by acidic Hg2+ catalyzed hydration of 3-methyl-1-butyne.
d) It forms a silver mirror on treatment with Ag(NH3)2.
e) This compound is an isomer of 4-penten-1-ol.

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3. Which of these methods would serve to prepare 1-phenyl-2-propanol?

a) Addition of benzyl Grignard reagent to acetaldehyde (ethanal).
b) Addition of phenyl lithium to propylene oxide (methyloxirane).
c) Addition of phenyl Grignard reagent to acetone (2-propanone).
d) Acid-catalyzed hydration (addition of water to) of 2-phenyl-1-propene.
e) Addition of methyl Grignard reagent to acetophenone (methyl phenyl ketone).
f) Addition of methyl Grignard reagent to phenylacetaldehyde.

11
Mani Pal Singh ·

koi post 202 mein help to kar do

PLEASE !!!!!!!!!!!!![2]

39
Dr.House ·

4. Oxidation Reactions of Alcohols
Simple 1º and 2º-alcohols in the gaseous state lose hydrogen when exposed to a hot copper surface. This catalytic dehydrogenation reaction produces aldehydes (as shown below) and ketones, and since the carbon atom bonded to the oxygen is oxidized, such alcohol to carbonyl conversions are generally referred to as oxidation reactions. Gas phase dehydrogenations of this kind are important in chemical manufacturing, but see little use in the research laboratory. Instead, alcohol oxidations are carried out in solution, using reactions in which the hydroxyl hydrogen is replaced by an atom or group that is readily eliminated together with the alpha-hydrogen. The decomposition of 1º and 2º-alkyl hypochlorites, referred to earlier, is an example of such a reaction.

RCH2–OH + hot Cu RCH=O + H2

RCH2–O–Cl + base RCH=O + H–Cl

The most generally useful reagents for oxidizing 1º and 2º-alcohols are chromic acid derivatives. Two such oxidants are Jones reagent (a solution of sodium dichromate in aqueous sulfuric acid) and pyridinium chlorochromate, C5H5NH(+)CrO3Cl(–), commonly named by the acronym PCC and used in methylene chloride solution. In each case a chromate ester of the alcohol substrate is believed to be an intermediate, which undergoes an E2-like elimination to the carbonyl product. The oxidation state of carbon increases by 2, while the chromium decreases by 3 (it is reduced). Since chromate reagents are a dark orange-red color (VI oxidation state) and chromium III compounds are normally green, the progress of these oxidations is easily observed. Indeed, this is the chemical transformation on which the Breathalizer test is based. The following equations illustrate some oxidations of alcohols, using the two reagents defined here. Both reagents effect the oxidation of 2º-alcohols to ketones, but the outcome of 1º-alcohol oxidations is different. Oxidation with the PCC reagent converts 1º-alcohols to aldehydes; whereas Jones reagent continues the oxidation to the carboxylic acid product, as shown in the second reaction. Reaction mechanisms for these transformations are displayed on clicking the "Show Mechanism" button. For the first two reactions the mechanism diagram also shows the oxidation states of carbon (blue Arabic numbers) and chromium (Roman numbers). The general base (B:) used in these mechanisms may be anything from water to pyridine, depending on the specific reaction.

11
Anirudh Narayanan ·

6)
The very first conversion that I'm attempting..........so pls forgive me if I'm wrong[2]

39
Dr.House ·

39
Dr.House ·

Two structural requirements for the oxidation to carbonyl products should now be obvious:
1. The carbon atom bonded to oxygen must also bear a hydrogen atom.
Tertiary alcohols (R3C–OH) cannot be oxidized in this fashion.
2. The oxygen atom must be bonded to a hydrogen atom so that a chromate ester intermediate (or other suitable leaving group) may be formed.
Ethers (R–O–R) cannot be oxidized in this fashion.

The fourth reaction above illustrates the failure of 3º-alcohols to undergo oxidation. The second reaction mechanism explains why 1º-alcohols undergo further oxidation by Jones reagent. The aqueous solvent system used with this reagent permits hydration (addition of water) to the aldehyde carbonyl group. The resulting hydrate (structure shown below the aldehyde) meets both the requirements stated above, and is further oxidized by the same chromate ester mechanism. Water is not present when the PCC reagent is used, so the oxidation stops at the aldehyde stage.
Another chromate oxidizing agent, similar to PCC, is pyridinium dichromate, (C5H5NH(+) )2 Cr2O7(–2), known by the acronym PDC. Both PCC and PDC are orange crystalline solids that are soluble in many organic solvents. Since PDC is less acidic than PCC it is often used to oxidize alcohols that may be sensitive to acids. In methylene chloride solution, PDC oxidizes 1º- and 2º-alcohols in roughly the same fashion as PCC, but much more slowly. However, in DMF solution saturated 1º-alcohols are oxidized to carboxylic acids. In both solvents allylic alcohols are oxidized efficiently to conjugated enals and enones respectively

39
Dr.House ·

39
Dr.House ·

19
Debotosh.. ·

tell me why 1,2 diketones give anhydrides in b.v. oxidation???????

39
Dr.House ·

39
Dr.House ·

11
Mani Pal Singh ·

1
sumit_kumar ·

good one....

39
Dr.House ·

Consider the possibility of the following reaction:

2-propanol
+
H3PO4 (conc.) and heat (>150 °C)

?

If you believe a reaction will take place, draw the structural formula for the chief organic product using the drawing window on the right. If no reaction is expected, draw the starting alcohol structure.

39
Dr.House ·

Consider the possibility of the following reaction:

cyclopentanol
+
PBr3 & heat

Consider the possibility of the following reaction:

2-methyl-1-propanol
+
C6H5CO2H, acid catalyst and heat

?

39
Dr.House ·

Consider the possibility of the following reaction:
cyclohexanol
+
Na (elemental metal)

Consider the possibility of the following reaction:
2-methyl-2-propanol
+
hydrazine (N2H4) & heat

39
Dr.House ·

Consider the possibility of the following reaction:
2-methyl-1-propanol
+
PBr3 & heat

39
Dr.House ·

Solve questions
Q.1. Two samples of HI each of 5 gm were taken separately in two vessel of volume 5& 10 ltr respectively at . The extent of dissociation of HI will be

1)more in 5 ltr vessel

2)more in 10 ltr vessel

3)equal in both vessel

4)NIL at both

Q.2) For the reaction the equilibrium constant is most likely to be changed by

1)The addition of acetic acid soln.

2) The addition of suitable catalyst.

3)The addition of acetate ion.

4) Heating the given mixture.

Q.3. At constant temp. , the equilibrium constant Kp for the decomposition of the reaction is expressed by

where P=pressure & x=extent of decomposition . Which of the following statement is true ?

1) Kp increases with increase of P.

2) Kp increase with increase of x.

3) Kp increase with decrease of x.

4)Kp remain constant with change in P & x.

Q.6.

Statement 1: Alkenes can give electrophilic as well as nucleophilic addition reactions.
and
Statement 2: Addition of HCl to CH2 = CH - Cl will mainly produce CH3 - CHCl2.

1. Statement 1 is True, statement 2 is True; statement 2 is a correct explanation for statement 1.

2. Statement 1 is True, statement 2 is True; statement 2 is not a correct explanation for statement 1.

3. Statement 1 is True, statement 2 is False.

4. Statement 1 is False, statement 2 is True.

Q.7. KMnO4 and MnO2 react in alkaline medium (KOH) to give K2MnO4. What is n factor of K2MnO4 in the reaction?

1. 3

2. 2

3. 2/3

4. 3/2

39
Dr.House ·

q1)two moles of an ideal gas are expand isothermally and irreversibly frm 1litre to 10litre at 300k.the enthalpy change in kj for the process is?

q2)the total energyin cal of one mole of an ideal monoatomic gas at 300k is ?

q3)for a 3dxy,, 3dy^2 electron ,the orbital angular momentum is?

11
Anirudh Narayanan ·

Both are easy. Similar processess for both:

1) take two beakers, one with the compound you have and the other with the compund u want

2) take a magician's hat and keep the beaker with the required product in it

3) assemble some friends to whom you want to show the conversions

4) widen your eyes and look up towards the sky and say "look! there's a white crow!"

5) In the fraction of the second that they look up, exchange the beakers

Your conversion is now complete in 5 steps.....

IMPORTANT NOTE:
Don't keep any harmful acids near you.......... cos your friends will take it and pour it on your face [3]

P.S:
This reply is not to be taken seriously. I know b555 won't... cos he thinks all of my replies are jokes [4]

39
Dr.House ·

OIL AND WATER CAN FORM A STABLE DISPERSION WITH THE HELP OF A THIRD SUBSTANCE .WHAT IS THAT SUBSTANCE?

Composition of a sample of wustite is Fe0.93 .What percentage of iron is present in the form of Fe(III)

When a bottle of perume is opened, odorous molecules mix with air and slowly diffuse throughout the entire room. which is correct for this process ?

a) G<0
b) S>0
c) H nearly equal to 0
d) S<0

1 mole of Fe0.9 O was dopped by 0.2 mole Ti4+ ions where Ti4+ replaced Fe+2 replaced Fe+2 in the crystal. this compound is dissolved in 1 litre of water & ten treated with 0.1N KMnO4 SOLUTION IN ACIDIC MEDIUM. calculate volume of KMnO4 required in ml

39
Dr.House ·

6]what are the lab tests to analyse the composition of coins(alloys)?

1
prateek punj ·

it is just the project.... my friend does the same test to analyse the cations present in the coins... it is just to analyse or fiind the cations...

1
voldy ·

8) you get glycerol and hexadecanoic acid.

39
Dr.House ·

YUP U R RIGHT PRATEEK

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