Tag: is

Which of the 3-d series of the transition metals exhibit the largest number of oxidation states and why ?

In case of transition metals the Manganese exhibit large range of oxidation state from +2 to +7. This is due to the fact that it has the highest number of unpaired electrons in its outer shell. The configuration of Mn is [Ar] 3d5 4s2 thius it can use its 7 electrons to show the large

Continue reading

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

Continue reading

Why Perchloric acid is stronger than sulphuric acid ?

The strength of an acid depends upon the oxidation state of the central atom. More is the oxidation state higher is the acidic character. In case of HClO4(perchloric acid) the oxidation state of chlorine is +7. And in case of H2SO4 (sulphuric acid) the oxidation state of Sulphur is +6 . The oxidation state of

Continue reading

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

Continue reading

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

Continue reading

How the age of mummies , dead bodies and fossils is calculated?

The aging of different organisms is mainly calculated by the special technique called the Radiocarbon dating. In this technique the age of any specimen is calculated on the basis of the present amount of an isotope of a particular element. Isotopes are the atoms of an element that have same atomic number but different atomic

Continue reading

Why does copper turns green on exposure to air ?

This happens because of corrosion of copper , as the copper is exposed to air it reacts slowly with water from the moisture present in air, carbondioxide and oxygen. And the product formed is a mixture of copper hydroxide and copper carbonate as shown below.

How many lone pairs of electrons are on the S atom in sulphur tetra floride (SF4) ?

In case of SF4 there are 6 electrons in the outermost shell of Sulphur, out of these 6 electrons, 4 are utilized in bonding with fluorine and thus two unshared electrons are there. Which leads to the lone pair as shown below. Contribute to make this site more informative.

What is hydrogen bond? How does an intermolecular hydrogen bond differ from intramolecular hydrogen bond ?

Actually the hydrogen bond is simply a type of attraction which is caused by the the electronegativity difference between hydrogen and highly electronegative element like oxygen carbon nitrogen and fluorine. Intermolecular hydrogen bonding takes place between two molecules having hydrogen and electronegative element. Hydrogen is attracted by the electronegative element of another molecule for example

Continue reading

Why H3PO3 is a diprotic acid? Give reason with structure .

Meaning of diprotic acid is that , it can loose two hydronium ions (H+) . For finding how many H+ ions it can give , we have to see its structure. Here it have only two hydroxyl groups that is -OH groups, and the hydrogen atoms joined to these only are ionisable. So only these

Continue reading

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

Continue reading

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

Continue reading

Semiconductor and its types.

The substances whose conductivity lies between 10-⁶ to 10⁴ ohm-¹ . The range lies between conductors and insulators. Types 1. n-type :- These type of semiconductors have excess electrons present in the lattice that are responsible for the conduction. These are formed when the group 14 elements like Silicon are doped with group 15 elements

Continue reading