Tag: chemistry

Is sublimation a chemical change or a physical change ?

In a physical change the nature of substance remains same . The properties remains same. But in case of chemical change the new kind of substance is formed, with different nature. “Sublimation is a process in which a substance changes its state from solid into vapour directly”. So the point to note here is that

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Why Carboxylic Acids are more acidic than phenols ?

In case of carboxylic acids the negative charge is on the more electronegative element that is oxygen as shown in the structure in both of the resonating structures. The negative charge on the more electronegative element makes it more stable. And thus it shows acidic character easily. But in case of phenols the negative charge

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SN1 mechanism

This mechanism is seen in Nucleophillic Substitution reactions, especially in those compounds in which the Carbon atom is more substituted . The rate of this mechanism depends on the step 1 where the leaving group leave with electron pair and leaves behind a carbocation. The whole rate depends only on one molecule. That’s why it

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The SN2 mechanism

This is a type of reaction mechanism that is seen in case of nucleophillic substitution reactions. It is BIMOLECULAR NUCLEOPHILLIC SUBSTITUTION mechanism. In this kind of mechanism two molecules decide the rate of reaction, so it is BIMOLECULAR mechanism. The whole mechanism proceeds through a single step. That concerted step involves the bond breaking and

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Stobbe reaction and its Mechanism

It is a type of condensation reaction that involves the condensation of an aldehyde or ketone with succinic ester in the presence of sodium ethoxide or Potassium ethoxide to yield unsaturated ester acid . The complete reaction is as below. The mechanism involves 3 steps , and firstly the succinate is treated with base to

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Why ortho-nitrophenol is more acidic than ortho-methoxy phenol ?

To answer this we have to see the reactive nature of phenol and the substituents attached to it. Acidic behavior of phenol depends on the fact that how easily it can loose a proton and make phenoxide ion which is stabilized by resonance. The methoxy group being electron donating group increases the electron density of

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Preparation of chlorobenzene – Sandmeyer’s reaction

Chlorobenzene and bromobenzene can be prepared by treating bezenediazonium chloride with cuprous chloride or cuprous bromide. This reaction is also called Sandmeyer’s reaction.

Why sigma bond is stronger than pi bond?

Actually the sigma bond involves head to head overlapping of orbitals, due to which the overlapping takes place on a larger extent. That makes the bond more stronger as compared to pie bond. In pie bond there is a sidewise overlapping of orbitals which leads to lesser extent of overlapping and thus the bond formed

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What are the factors that affect Vapour Pressure?

1.Temperature :- With increase in temperature the rate of vaporization also increase thus it creates more pressure. Moreover with increase in temperature the kinetic energy of the vapours also increase. 2. Nature of liquid:- The liquids with lower inter-particulate attractions have high vapour pressure as the formation of vapours is easy . Like acetone is

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Calculation of edge length and radius of atom.

Calculate the radius of copper atom if it crystallise in face centred cubic lattice and has a density of 8.93 g / cm cube. Solution Structure given = fcc For fcc , Z = 4 Density , d = 8.93 Molar mass , M = 63.55 Avogadro number = 6.2×10^23 Use the given formula In

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Which set of elements has a strong tendency to form cations? Or which of the elements are the most electropositive elements?

The elements belonging to Group 1 and group 2 of periodic table has the strong tendency to form cations. The reason behind this tendency is that the elements belonging to group 1 and 2 have one and two valance electrons respectively. By loosing the valence electrons, they will aquire noble gas configuration. It is easy

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What are the chemical properties of Carboxylic Acids ?