# All Questions

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### Why can't sodium borohydride reduce carboxylic acid and ester groups?

Sodium borohydride ($\ce{NaBH_4}$) is a reducing agent used in various organic reaction to reduce aldehydes, ketones and acyl chlorides. Why can't sodium borohydride reduce carboxylic acid groups and ...
75 views

### Does the position of a functional group in an organic compound have any effect on the compound's heat of combustion?

Is there a link between where the functional group is located in an organic compound and the compound's heat of combustion? It has been mentioned before that it is difficult to accurately get the ...
25 views

### Which of these can undergo decarboxylation reaction readily

Which of these carboxylic acids can undergo decarboxylation readily? According to what I know beta-keto acids undergo decarboxylation easily and readily due to formation of a stable intermediate. So ...
1k views

### Using Dalton's law of partial pressure to find percentages of composition

A mixture of helium and neon gases is collected over water at $28.0 \rm~^\circ C$ and $745\rm~ mmHg$. If the partial pressure of helium is $368\rm~ mmHg$, what is the partial pressure of neon? (Vapor ...
11 views

### How to make SiC (silicon carbide) at home?

I have found this wikipedia page talk about Acheson process, the simplest way to make SiC. But can I really do something like that in my house? I just want to make some LED myself from SiC (not just ...
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### Which process would separate the mixture of toluene, cyclohexane and water?

toluene: $\ce{C6H5-CH3}$ cyclohexane: $\ce{C6H12}$ I think that answer would be: Toluene and cyclohexane do not dissolve in water (since they are nonpolar), so I would first separate the water from ...
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### Glycerin yield upon saponification of beeswax

I am making a custom grease (castor oil & sodium stearate) that will be suspended in beeswax. I have found that saponifying some beeswax for use in the grease results in higher operating ...
38 views

### What is the name of a reaction that produces 3 compounds? [closed]

I was wondering if anyone knows what kind of reaction the following is: $$\ce{Na2SiO3 + 6HF -> SiF4 + 2NaF + 3H2O}$$
53k views

### Why doesn't copper react with hydrochloric acid while the other metals do?

5) Which one of the following metals does not react with hydrochloric acid? A. zinc B. magnesium C. iron D. copper E. aluminium The right answer must be copper, but why ...
28 views

### Why are enthalpy of combustion and molar mass of organic compounds proportional?

I noticed that when you graph heat of combustion against molar mass, you get a completely straight line with a correlation of 1. I know that the longer the chain is, the stronger the LDF get, so it is ...
13 views

### How to generate accurate displacements along normal modes?

How can i displace my structure along a particular normal mode, without coupling to other modes ? Rather than a exact mathematical procedure, I am more interested in a software/script/package that can ...
2k views

### Why does hydrogen burn with a pale blue flame while its emission spectral lines are red in colour?

I was studying oxidising flames and realized that sodium burns with a bright yellow flame the wavelength of which is around 588 nm. Then I searched for emission spectra of sodium and found that the ...
20 views

### Vanadium redox battery… why not nitrogen redox battery OR iron redox battery?

Vanadium redox battery operating on \begin{align} \ce{V^2+ -> V^3+ +e-}\\ \ce{VO2^+ +e- +2H^+ -> VO^2+ +H2O} \end{align} because Vanadium has multiple oxidation states. How about nitrogen ...
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### Normal melting point

Consider the following data for a substance: Critical point: 114.3 atm and 561°C Triple point: 0.108 atm and 114°C Normal melting point: 1.00 atm and 124°C What is the normal boiling point of the ...
75 views

### What is the mechanism of formation of alkali metal superoxide?

I was studying about alkali metals. I can get how oxides and peroxides are formed. In alkali metal oxides, both of the bonds of the dioxygen molecule first undergoes homolytic cleavage, then the ...
5k views

### Order of dipole moments

What is the order of dipole moments for $\ce{SO3, SiO2, P2O5,}$ and $\ce{Cl2O7}$? This question is from a book and the answer given is $\ce{Cl2O7 < SO3 < P2O5 < SiO2}$. Can someone explain ...
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### How to use Sodium Thiosulfate for fixing dicopper (I) tetraiodomercurate (II)?

DISCLAIMER DO NOT TRY TO DEMERCURATE USING DESCRIBED PROCEDURE. CONSULT YOUR EMERGENCY SERVICE. I found a discrepancy between a government-approved procedure of living quarters demercuration and the ...
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### Reaction of but-2-ene with Cl2/CCl4

I have often studied the reaction of Br2/CCl4 with But-2-ene which results in formation of But I wondered what would be formed if Cl2/CCl4 reacts with But-2-ene. Does it lead to the formation of ...
167 views

### Finding order of acidic strength for given compounds

The decreasing order of acid strength of the following compounds: The given compounds are Water ($\ce{H2O}$) Ammonia ($\ce{NH3}$) Acetylene ($\ce{C2H2}$) Triphenyl system ($\ce{Ph3CH}$) a) $\ce{NH3}$ &...
57 views

### Triple Point of a compound and critical point

Is it necessary for all compounds to have a triple point? Also, how is the triple point determined? Suppose a substance does not have a triple point, so how do researchers agree on the impossibility ...
6k views

### Where to find data for Gibbs energy, enthalpy, and entropy?

Where can you find the enthalpy and Gibbs free energy of formation and entropy of compounds either as a data file or web API? Technically, I only need two since I can figure out the other one from two ...
6 views

### Chemistry database for Gibbs energy [duplicate]

Is there good databases for Gibbs energy and other thermal properties? NIST WebBook is okay but easier to browse most common chemical elements like hydrogen, water, oxygen and so on in a table or ...
31 views

### Determining whether a compound is ionic or molecular in nature

$\ce{HCl}$ is a molecular compound because there is a covalent bond between $\ce{H+}$(a proton) and $\ce{Cl-}$ (a chloride ion) $\ce{NH4NO3}$ is an ionic compound because there is an ionic bond ...
32 views

### Reason for triphenyl methane being less acidic than acetylene

This question came through answering a question that talked about the acidic order of four compounds. Upon researching the actual $\mathrm p K_\mathrm a$ values I noticed that even though there was a ...
22 views

### Thermodynamic properties of enantiomers

Pairs of enantiomers have the same chemical and physical properties (except rotation of plane polarized light) within an achiral environment. However, I am curious about the thermodynamic properties ...
14 views

### Temperature relation with concentration and volume

Q. Standard enthaply change for the reaction of calcium hydroxide with hydrocloric acid was found by reacting $\pu{0.0100 mol}$ of solid calicum hydroxide with $\pu{50 cm^3}$ of a $\pu{1.00 mol/dm^3}$ ...
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### Does a geminal or vicinal diiodide form upon addition of excess HI to but-2-yne?

Reaction: $\ce{CH3-C#C-CH3 + HI (excess) -> ?}$ Product : I thought of different carbons by the reasoning from this post earlier I posted. But it is given that both iodine atoms exist on the same ...
26 views

### Given initial moles of weak acid, find moles of conjugate base to be added to get a final pH (volume unknown)

I am preparing notes on buffers and I came across this problem on a website: Given 10.0 mmol of a weak acid HA with $\textrm{p}K_a =5$, how many mmol of NaA needs to be added to have a final \$\textrm{...
64 views

### Can sodium borohydride reduce hemiacetals?

In the synthesis of Panacene by Canesi et al. [1], a step involves the installation of an -OH group on a double bond, using the oxymercuration-demercuration procedure. However, the product happens to ...
29 views

### Why do only cations move into interstitial sites in Frenkel Defect?

I have learnt that cations move into interstitial sites due to their smaller size in comparison with anions according to my teacher when learning about crystal defects today. My question is, why ...
17 views

### HOBt and DCC in the synthesis of peptides

DCC is a well known reagent used for the synthesis of peptides, aiding the formation of the amide bond by forming an intermediate with the carboxylic acid that contains a leaving group. During my ...
3k views

### Why are more electronegative atoms better leaving groups?

My book says, "halide anions are electronegative and can easily stabilise negative charge, hence are good leaving groups." What exactly does "stabilising negative charge" mean? I ...
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### How reliable would commercially available starch be as a standard for an experiment?

I am conducting a student experiment of finding the amylose to amylopectin ratio of certain samples using an iodine colorimetry method. In order to calculate the actual ratios, I need a standard to ...
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### Kohlrausch's Law

What is the proof of Kohlrausch's Law of Independent Migration of Ions? How did Kohlrausch calculate the limiting molar conductance of a weak electrolyte? I am asking this in context of ...