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Reaction molecularity and order
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15 votes

First of all, Molecularity isn't defined for a complex reaction. From Physical Chemistry by Ira. N Levine: (Page 531, Rate Laws And Equilibrium Constants For Elementary Reactions ): The number of ...

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Acidity order of nitrophenols
14 votes

You have correctly identified that m-nitrophenol should be the weakest acid among the isomers as the resulting anion cannot be stabilised by the $\text{-M}$ effect of nitro group owing to its meta ...

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Which has higher lattice energy: MgO or LiF?
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14 votes

$\ce {MgO}$ ($\approx 3800$ $\pu{kJ mol^{-1}}$) has higher lattice energy than $\ce {LiF}$ ($\approx 1045$ $\pu{kJ mol^{-1}}$) mainly because of the greater charge on $\ce{Mg^2^{+}}$ ion and $\ce {O^{...

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Why is cis-1,2-dichloroethene more stable than trans-1,2-dichloroethene?
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12 votes

Here's a pre-MOT rationalisation of the cis form being more stable than the trans form for 1,2-dihaloethylenes: The lone pair of chlorine atoms is involved in resonance with the double bond, as it ...

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What is the reason for the exceptional stability of the cyclopropylmethyl carbocation?
10 votes

Cyclopropane is a highly strained molecule with a bond angle of $60^\circ$. The normal tetrahedral bond angle is $\pu{109^\circ{28}'}$, so we'd expect a ring strain of $49.28^\circ$! For a ...

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Mechanism of formation of 2-naphthol red dye (aka Sudan 1)
9 votes

The formation of para-red is an example of electrophilic aromatic substitution. The electrophile reacts with the ring carbon that is ortho to both the activating group ($\ce{-OH}$) and the other ...

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Why is dinitrogen tetraoxide less stable at high temperature?
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8 votes

I figured out the answer using Van't Hoff Equation: $$\ln\left(\frac{\ce{K_2}}{\ce{K_1}}\right)=-\frac{\ce{\Delta H}}{\ce{R}}\left({\frac{1}{\ce{T_2}}-\frac{1}{\ce{T_1}}}\right)$$ Let's assume that $\...

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Are there any substituents other than halogens which are ortho-para directors but ring deactivators?
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7 votes

The nitroso $\ce{-NO}$ group is deactivating as well as ortho para directing just like the halogens in electrophilic aromatic substitution. For reasons of this behaviour, refer to this question on ...

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What is non PV work? How is it related to Gibbs energy?
6 votes

At constant temperature and pressure, the maximum non expansion work is given by the change in the Gibbs Free Energy. $$dW_{\text{max}}= dG$$ Proof: At constant temperature and pressure, from ...

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What do "degrees of freedom" refer to?
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5 votes

To find the number of degrees of freedom of a system, ask yourself the question, "in how many ways can I describe the motion of this system?" Let us begin with monoatomic gaseous molecules. ...

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Heating p-Bromobenzenesulfonic acid in the presence of dilute HCl
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5 votes

I think @ron has hit the bull's eye in the comments! I would like to elaborate upon that: Since each step in the sulfonation of benzene is an equilbirum, sulfonation is a reversible reaction. ...

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Enthalpy calculation
5 votes

$$\ce{X + 2Y -> 2Z}$$ \begin{align} \ce{W + X &-> 2Y} &\qquad &\Delta_\mathrm{r}H_1 = \pu{-200 kcal} \tag{1}\\ \ce{2W + 3X &-> 2Z + 2Y} &\qquad & \Delta_\mathrm{r}...

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Meso and achiral does both term means the same?
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4 votes

From the Gold book: meso-compound: A term for the achiral member(s) of a set of diastereoisomers which also includes one or more chiral members Achiral compound: A compound that can be superimposed ...

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Why is allyl chloride more reactive towards substitution than alkyl chloride?
4 votes

But how allyl halide is more reactive than alkyl halide? Reactivity towards $\ce{S_N1}$ The key to reactivity towards $\ce{S_N1}$ is the stability of the formed carbocation. Allyl system stabilises ...

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Why only F, O and N form Hydrogen Bonds?
4 votes

No, that's not necessary. Amongst the strongest hydrogen bonds are formed by $\ce{ N, O, F}$ because of their high electronegativity. There's evidence that the ions $\ce{Cl-, I-, Br- }$ form ...

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Is heat an extensive or intensive property?
3 votes

You seem to be confused between internal energy and heat. An object does not "possess" heat. The correct term to describe the energy possessed by it due to molecular motions and other microscopic ...

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What exactly does the "per mole" unit of heat of atomization mean?
3 votes

According to Wikipedia, Standard enthalpy of atomization is the enthalpy change when $1$ mole of gaseous atoms is formed from its element in its defined physical state under standard conditions $(\...

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Equivalent conductivity of barium chloride at infinite dilution
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2 votes

One must be really careful with the units while dealing with conductivity, conductance problems. If you read the question carefully, the equivalent conductivity of $\ce{Ba^{2+}}$ and $\ce{Cl^{-1}}$ ...

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What is the configuration of dimethyl[tris(trifluoromethyl)]-λ⁵-phosphane?
2 votes

You can note that $\ce{-CH3}$ shows electron releasing (+I) effect while $\ce{-CF3}$ shows strong electron withdrawing effect. Now, you can treat inductive effect as the organic analogue of ...

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Is the electrophile in sulfonation of benzene SO3 or SO3H+?
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2 votes

From Clayden, under the heading "Sulfonation of Benzene" (electrophilic aromatic substitution): The cationic intermediate can also be formed by the protonation of sulfur trioxide, $\ce{SO3}$, ...

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What is the reaction mechanism of nitrogen leaving from diazo compounds?
2 votes

The reaction is $\ce{S_N1}$ Among the evidence for the $\ce{S_N1}$ mechanism with aryl cations as intermediates, is the following: The reaction rate is first order in diazonium salt ...

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Which is more acidic: p-xylene or 3-methoxytoluene?
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2 votes

$\text{Acidic Strength}\propto \text{-I, -M, Negative Hyperconjugation effects} \propto \dfrac{1}{\text{+I, +M, +Hyperconjugation effect}}$ Recall that $\ce{-OCH3}$ is a moderately activating group ...

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Compare the work done during dissolution of carbides
2 votes

The relevant equations are: $\ce{Mg2C3(s) + 4 H2O (aq) -> C3H4 (g) + 2Mg(OH)2 (aq)}$ $\ce{Al4C3 (s) + 12H2O(aq) -> 3CH4(g) + 4Al(OH)3(aq) }$ $\ce{CaC2(s) + 2H2O(aq) -> C2H2(g) + Ca(OH)2(...

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Reactivity of meta- and para-bromo-nitrobenzene towards nucleophilic substitution
1 votes

The mechanism generally followed in nucleophilic aromatic substitution when an activating group (like $\ce{-NO2}$) is present on the ring is SNAr. The first step, the formation of the carbanion, is ...

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