Questions tagged [isomers]

Compounds that have identical molecular formula but different chemical structure.

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5
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0answers
46 views

Type of chirality in polycyclic compounds

Ignoring whether or not this molecule could exist, is there a name for this type of chirality? This molecule's mirror image cannot be superimposed on itself but there are no chiral centres. Even ...
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28 views

Molar conductivity in compounds showing coordination isomerism

Question Which of the following complex has lowest molar conductivity? $\ce{[Co(NH3)6][Cr(NO2)6]}$ $\ce{[Cr(NH3)5(NO2)][Co(NH3)(NO2)5]}$ $\ce{[Cr(NH3)4(NO2)2][Co(NH3)2(NO2)4]}$ $\ce{[Co(NH3)5(NO2)][...
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1answer
202 views

Stereo-isomerism in 7-methylbicyclo[2.2.1]hept-2-ene

The above are two compounds. The objective is to find if the compounds are identical/enantiomers/diastereomers I can see a plane of symmetry if we keep the $\ce{H-C-CH3}$ in the plane. So, ...
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1answer
60 views

Comparing the solubility of glucaric acid and mucic acid

Why is glucaric acid soluble in water but not mucic acid? The chemical formulae seem to be the same so why is it that one is more soluble than the other?
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1answer
417 views

Anomalous boiling point of “iso-” alkanes

I was attempting to compare the boiling points of iso-hexane and 3-methylpentane. Boiling points of organic compounds depend upon three factors according to Master Organic Chemistry – 3 Trends That ...
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1answer
34 views

Temperature relation for isomerism reactions

When we have an isotherm isomerism reaction $\ce{A(g) -> A^*(g)}$ with $\ce{ΔH^0 = 0}$ is the ratio of preassures $\ce{P_A^* / P_A}$ independent from temperature?
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1answer
44 views

Is tertiary-butyl same as neo-butyl?

By definition neoalkanes have two-times branching of methylgroup at second last carbon. But in no book which I could find ,it is not alternatively named as neo-butyl. Is the definition right, or am I ...
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3answers
252 views

Diastereomers or not

Why is the first one not a pair of diastereomers while the second is? The only reason I could think of was in the first $\ce{Me}$ is the same as $\ce{CH3}$ that is same groups even though differently ...
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1answer
424 views

How is plane polarized light rotated by chiral compounds? [duplicate]

There are plenty of questions related to this topic on this site but no proper answer. Can anyone please explain to me how plane polarized light is rotated by chiral compounds, and why it cannot be ...
2
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0answers
23 views

Isomerization of phosphorylated 2-imino-1,3-dioxalanes into phosphorylated cyclic carbamates

I found a patent dating back to the Soviet Union. The patent number is 256764, and the patent describes the synthesis of phosphorylated cyclic carbamates. Here is a section of the patent, followed by ...
3
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1answer
118 views

Number of Stereoisomers of C(CHClCH3)4

I am having trouble understanding why the structure $$\ce{C(CHClMe)4}$$ has only five stereo isomers. According to my textbook, the stereo isomers correspond to the following series of absolute ...
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1answer
100 views

Optical activity of 3‐chlorobutan‐2‐ol

In the picture that I have uploaded, I have read that the given compound is chiral. But on drawing the sawhorse structures (for better visualisation), I feel like the compound is symmetric about a ...
3
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1answer
75 views

Structural isomers of hexaammineiron(III) hexacyanidocobaltate(III)

Find the number of structural isomers of $\ce{[Fe(NH_3)_6][Co(CN)_6]}$ This was a question solved by my teacher as follows: The $\ce{CN}$ will show linkage isomerism while $\ce{NH_3}$ and $\ce{CN}$ ...
3
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1answer
106 views

Total number of stereoisomers of truxillic acid

Total number of stereoisomers of the compound will be: This was a question asked in our mock test. I've tried by considering pseudo-chirality on the carbon atoms. But I don't know where to start. I ...
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1answer
51 views

Type of structural isomerism

What is the type of structural isomerism in which isotopes move around? Examples $\ce{CH2D-NH2}$ and $\ce{CH3-NHD}$ $\ce{CH2D-NH-CH3}$ and $\ce{CH3-ND-CH3}$ $\ce{CH2D-NH-CH2CH3}$ and $\ce{CH3-NH-CHD-...
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Cis-Trans Isomers Heat of Combustion

Consider the 4 cis-trans isomers for the above compound. In what way would the cis-trans isomers affect their heat of combustion. I think that if the substituents are on alternating sides of the ...
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0answers
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Strains in conformations of cyclohexane

I know some the basic kind of strains that can exist in molecules namely Torsional strain (Vanderwaals' strain), steric strain and angle strain. Is it possible to associate a particular type of ...
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1answer
148 views

MA3B3 isomers - is this same as meridional one? [closed]

I'm new to studying stereo chemistry. (Now I'm studying coordination complexes.) In my class material and other some datas(from google), it says that there is two, fac and mer. I want to know is ...
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2answers
121 views

How to check which compound will show optical isomerism?

So my teacher told that those compounds which have one or more chiral carbon present in them it will definitely show optical isomerism because it has an optically active stereoisomer, but there are ...
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2answers
70 views

Find the number of geometrical and optical isomers of 1,2,3,6-tetramethyl cyclohex-1,4-diene

The compound given to me is 1,2,3,6-tetramethyl cyclohex-1,4-diene. The geometrical isomers for the following compounds are: The isomer on the right can also be an optical isomer with its enantiomer....
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4answers
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How is exact racemization possible? [closed]

A racemate consists of 50 % $d$ and 50 % $l$ forms of an optically active compound. But how can someone ensure exact 50% quantity comparing molecule by molecule? There will always be some difference ...
3
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2answers
128 views

Number of optically active isomers of [Co(NH3)2Cl2(NO)(OH)]?

My Attempt: Since Compound is of the form M[a2b2cd] I got three optically active isomers of the form M[(ab)(ab)(cd)] , M[(ab)(ac)(bd)] , M[(ab)(bc)(ad)] and since NO is a bidentate ligand, total ...
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1answer
93 views

How is 1,4,6-trichlorodiamantane optically inactive? [closed]

How this compound is optically inactive I can't analyse any element of symmetry in this compound.
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How many non-cyclic isomers exist for C4H7Br? [closed]

The compound Q has the formula $\ce{C4H7Br}$ and contains a double bond. How many non-cyclic isomers exist for Q? Should include cis-trans and any other form of isomers as well.
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1answer
185 views

Why is 3,6-dimethylpiperazine-2,5-dione optically active in spite of having a centre of symmetry?

I learnt in my chemistry class that if a molecule has an element of symmetry (either a plane of symmetry or a centre of symmetry), it will not be chiral and hence will not show optical activity. My ...
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1answer
71 views

Does tris(ethylenediamine)iron(III) exhibit optical isomerism? [closed]

I'm studying 12th. In my book they mentioned that $\ce{[Co(en)3]^3+}$ exhibits optical isomerism. But in that same book, there is a question Which of this doesn't exhibit isomerism? and the ...
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0answers
49 views

Why are branched isomers less polarisable?

This fact was given as an explanation as to why branched isomers of a compound have lower boiling points. How are branched isomers less polarisable and how does this relate to London dispersion ...
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0answers
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Do any pharmaceuticals increase in potency or toxicity over time?

Pursuing a question raised in these comments: Are there any known pharmaceuticals that increase in potency or toxicity during storage, or over periods of months to years? If not, what if we broaden ...
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0answers
19 views

Why are these compounds classified as metamers? [duplicate]

Metamers are compounds having the same molecular formula but different number of carbon atoms, on either side of functional group. In the above compounds, the number of carbon atoms around the ester ...
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1answer
1k views

Number of possible isomers (including optical/geometric ones) with C4H8O molecular formula [closed]

I found 32 isomers but I think I made a miscount. Chain alcohols: 6, chain ethers: 5, and chain carbonyl compounds (ketones/aldehydes): 3 Three-member ring alcohols: 7, three-member ethers: 6 (...
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305 views

How many isomers are there of dimethylcyclopentane ( neglecting enantiomers )?

The book says the answer is 5 but i was able to draw much more than that like Methylcyclohexane ,propylcyclobutane ,1-Ethyl-2-methylcyclobutane ,1-Ethyl-2,3-dimethylcyclopropane,1-Methyl-2-...
2
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1answer
72 views

The number of optical isomers of 3,4-dichlorobutan-2-ol

The number of optical isomers possible for the given organic molecule is? $\ce{CH_3-C^*H(OH)-CHCl-CH_2Cl}$ (the configuration is fixed at $\ce{C^*}$) The given answer is 2. The carbon marked with an ...
10
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4answers
538 views

Stability of 4-pyridone vs 4-pyridinol

In kryptomerism assignment, there was a question to compare more stable tautomeric form between 4-pyridone (1) and 4-pyridinol (2): Answer: 4-pyridone. My friend gave two plausible reasons: $\ce{C=...
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1answer
87 views

Which of the following isomers of 2,3‐dihydroxy‐4‐methoxy‐4‐oxobutanoic acid are identical?

Which of the following are identical? A and B are identical A and B are diastereomers A and C are enantiomers A and B are enantiomers What I know is that when we rotate a Fisher projection by 180°, ...
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1answer
163 views

Conformers of a meso-compound [duplicate]

In a particular question in one of my reference book, I was asked if the given compound (meso-butane-2,3-diol) was a meso compound or not. In it’s solution part, to show that the compound was ...
1
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1answer
320 views

Optical activity of cis coordination compounds

I came across a statement saying, "Consider a Octahedral coordination compound of type [MA2X2]. Then, if the compound is in a cis form, it shows optical activity as there is no plane of ...
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1answer
303 views

Number of Stereoisomers for Terpin

Terpin (4-(2-hydroxypropan-2-yl)-1-methylcyclohexan-1-ol) has two $\mathrm{sp^3}$ carbons with different substituents on a cycloalkane, so it has two cis-/trans-isomers, and from what I was taught, is ...
2
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0answers
59 views

How to apply the $parvo/amplo$ akamptisomeric stereodescriptors to this bicyclic system?

I'm looking for examples of akamptisomerism[1]. I'm try to find simple molecules able to (theoretically) show this kind of isomerism. I thought about the isomers of (2R)-2-methyl-9-oxabicyclo[3.3.1]...
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Cis/trans with alkene substituents on cycloalkanes

My chemistry book is saying that the double bond indicated by the red arrow can generate cis/trans isomers: I don't understand how this can be so, as you need to use E/Z priority rules in this case. ...
5
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1answer
321 views

What is the physical state of vitamin E acetate at room temperature and normal pressure

Vitamin E acetate ((+)-alpha-tocopherol acetate) is sold as semi-solid/liquid by Sigma and their safety data sheet gives the melting point as 25 °C. On the other hand, internet databases such as ...
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2answers
78 views

Why are we still using cis/trans system while the E/Z system is better than it?

I am currently learning about Alkenes. It is given that cis/trans isomerism is either ambiguous or doesn't even apply in cases where the alkene is trisubstituted or tetrasubstituted. To solve this ...
2
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1answer
615 views

What is the number of stereoisomers for hex-4-en-2-ol?

For the following compound, find Total number of stereoisomers Number of optically active stereoisomers Total number of fractions on fractional distillation of all stereoisomers ...
2
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1answer
1k views

How there are 7 enolizable hydrogens in 2‐methylcyclohex‐2‐en‐1‐one?

49. How many enolizable hydrogens are there in the following compound? (a) 2 (b) 4 (c) 5 (d) 7 I know that enolate ion is the anion formed when an α-hydrogen in the molecule of an aldehyde or ketone ...
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1answer
144 views

how is there no centre of symmetry in this case? [closed]

the question was whether the following compounds have the center of symmetry or not .the question was : And the answer is that there is no center of symmetry .how? according to me, there should be ...
3
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1answer
443 views

Point group of cis- and trans-decalin

What is the point group of of cis- and trans-decalin? I watched a video saying that it is $C_\mathrm{2h}$ for cis-isomer, but my friend says it is $D_\mathrm{2h}.$ I'm so confused.
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1answer
2k views

what will be the priority order?

if any two compounds happen to show tautomerism, ring chain isomerism, functional isomerism, metamerism, chain isomerism as well as position isomerism, what priority order do we follow to assign them ...
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0answers
445 views

How ethylbenzene and 1,2‐xylene are chain isomers?

How the following two structures are chain isomers? According to what I have studied in nomenclature when a compound has both cyclic and straight chain, we consider that the chain as parent chain ...
3
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2answers
2k views

How many ether metamers are possible for C4H10O?

How many ether metamers are possible for $\ce{C4H10O}?$ According to me, the answer should be 2 but it was given 3. I know 3 structures can be made: $$\ce{CH3—O—CH2—CH2—CH3}\tag{1}$$ $$\ce{CH3—CH2—...
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25 views

How would you order alkyl groups of this compound numerically? [closed]

If akyl groups are ordered alphabetically and ethyl comes before methyl, would this compound be called 2-ethyl-3,4 dimethyl pentane? Since that would be less than 4-ethyl-2,3 dimethyl pentane, correct?...
3
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1answer
142 views

Number of stereoisomers of polysubstituted cubane

The molecule given below is a substituted cubane. a) How many stereoisomers exist for this molecule? b) How many pairs of enantiomers are possible? How do I calculate the number of stereoisomers? ...

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