What is Hardy-Schulze rule ?
Hardy-Schulze rule It has two postulates (i) The ions which carry charge opposite to the particles of sol are more effective in causing the coagulation of the solution. (ii) Coagulating power of an electrolyte is directly proportional to the fourth power of the valency of the ions causing coagulation.
Why there’s no repulsion between electron in a coordinate bond?
The coordinate bond is formed by the overlapping of d-orbital of Central metal atom and the ligands. The d-orbitals are enough large that there is not any chance of repulsion between the resulting bond formation between the ligand and the metal atom. Thus there isn’t any repulsion.
What happens when gelatin is added to gold solution ??
On addition of gelatin , the gold solution starts behaving like a lyophilic colloid . Otherwise the gold solution is lyophillic colliod.
What is peptization ?
The process of converting a precipitate into a colloidal solution by shaking vigorously with a small amount of electrolyte. The electrolyte used here for creating a colloidal solution is called the peptising agent .
Why lyophobic colloidal solutions are easily coagulated ?
Lyos – solution, phobic – hating(fear) Firstly in this case we have to understand that the lyophobic colloids are those in which the dispersed phase do not have affinity for the dispersion medium. So if we add any suitable electrolyte in it , the colloidal solution easily gets coagulated.
Why aeroplane leaves behind white trail in winters or cool weather ?
Hi guys today we are going to talk about the white trail formation during the winter, when an aeroplane flies. To understand this phenomenon we must be aware of the combustion process taking place at the time of working of engine. During the combustion process, carbondioxide and water vapours are the major products. The water […]
What is electrophoresis?
When electric potential is applied across two platinum electrodes which are dipped in a colloidal solution, the colloidal particles move towards the electrodes. This movement of particles on application of electric potential is called electrophoresis.
What are Multimolecular and Macromolecular colloids?
Multimolecular colloids are formed when the molecules of dispersed phase aggregate to make a molecule which is having the size between 1nm to 1000nm. The point to note here is , the particles of colloidal solution were of molecular size which joined to make Multimolecular system. Macromolecular colloids are the substances in which the size […]
Why sky appears blue in colour ?
The particles of atmosphere which are of colloidal size can easily scatter the blue component of the light. The wavelength of blue light allows its scattering easily. That’s why it appears blue in colour.
What is the shielding effect? How does it affect the size of an element?
The shielding effect , is seen when the electrons of inner shells shield the outer shell electrons from the nuclear charge. And this decreases the effective nuclear charge for the outer shell electrons. And hence they are less attracted towards the nucleus. This happens because of the higher penitration of the inner shell electrons. The […]
What are isoelectric species? And What determines the difference in the size of atoms or ions if they are isoelectronic ?
Isoelectric species are simply the atoms or ions that have same number of electrons. For example:- Na+ , Ne , F- , O²- , Mg²+ And their size depends upon the effective nuclear charge , in case of cations the number of protons is higher than that of electrons thus their size is smaller than […]
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.
Which isomer is more steam volatile ortho nitrophenol or para nitrophenol ?
Ortho isomer shows intramolecular hydrogen bonding , in which the H-bonding takes place in a single molecule not with the adjacent molecule. And in that case the molecules exists as discrete molecules or particles only because they are not attached or attracted by each other. Thus their boiling point decreases and they are volatile. But […]
Which of the following has the largest number of atoms (A. 1g of H2 B. 1g of O2 C. 1g of N2 D. 1g of F2)?
2g of H2 = 1mole = 6.022 x 10²³molecules So 1 g of H2 will have = 1/2 mole = 6.022 x 10²³ / 2molecules Number of atoms in hydrogen molecule = 2 Number of atoms in 1 g of H2 = 3.011 x 10²³ 32 g of O2 = 1 mole = 6.022 x […]
Why is Krypton larger in size than bromine,even if atomic radius decreases while going from left to right across a period?
In case of Krypton being and inert gas it do not make any Bond and remains as as a single molecule due to this we calculate the Van der waal’s radius in case of these . Which is always larger as compared to other elements. But in case of bromine we calculate the ionic radius […]
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 […]
What is gold number ?
It is the amount of lyophilic sol required in milligrams to prevent the the coagulation of 10ml gold sol by the addition of 1 ml, 10% NaCl solution .
Why the electron affinity or electron gain enthalpy of Chlorine is higher than Fluorine ? Even if Fluorine is most electronegative element.
Even if the Fluorine is most electronegative element still its electron gain enthalpy is lower than Chlorine. In case of Fluorine the size of valence shell is so small that the upcoming electron experiences repulsions so it is not practically easy for Fluorine to gain an electron as compared to Chlorine. On other hand in […]
What are Colligative properties ?
Actually the word co-ligative itself reveals that (“co” means each other and “ligative” means related) These are the properties which are related to each other. The colligative properties are those properties that depend on the number of solute particles in a solution or a mixture. “These properties don’t depend upon the nature of particles “. […]
Why is carbon important for forming complicated molecules? Or why carbon makes a large number of molecules ?
The answer to this question is very simple . There are two major reasons behind it. 1. Catenation :- It is the property by which the carbon can make long chains, branched chains and ring or cylic structural by joining with its own atoms. Due to this it can make a variety of molecules. 2. […]
Why are the noble gases chemically inert?
The outer or valence shell of these elements is complete. And they need not to make any bond. They do not share or transfer the electrons . Due to fully filled orbitals, Their ionisation enthalpies are also very high. So removing an electron from them is also very difficult. The examples of these are Helium, […]
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 […]
Why white phosphorus is more reactive than red phosphorus?
White phosphorus exists in p4 molecule. In the molecular strain is quite high and it tends to break it as early as possible. On the other hand red phosphorus exists as polymer like structure. In red phosphorus the molecules join to make long chains and that makes them chemically inert or less reactive. For study […]
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 […]
What is the structure of XeOF4 and XeO3 ?
The structure of XeOF4 is square pyramidal. And its hybridization is sp³d² The structure of XeO3 is pyramidal and its hybridization is sp³.
What is Wurtz reaction?
It is the reaction between alkyl halides and sodium in the dry ether to give alkanes with higher number of carbon. 2R-X + 2 Na —> R-R +2NaX
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 […]
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 […]
Why glass is considered as super cooled liquid ?
It is an amorphous solid. In these kind of solids the particles are not properly arranged and it is assumed that the particles do not get enough time to set into a proper arrangement. So these are considered as super cooled liquids.
What is Coordination number
It is the number of lattice points touching one lattice point in a crystalline solid. For example in case of Sodium chloride it is 6 .
Explanation of Paramagnetism, ferromagnetism, ferrimagnetism and antiferromagnetism .
1. Paramagnetism :- This is the phenomenon by which substances are weekly attracted by the magnetic field. It arises because the substances are magnetized in the same direction of the applied magnetic field. This property is shown by the atom, ions or the molecules that contain unpaired electrons. 2. Ferromagnetism:- This is the phenomenon by […]
What are Amphoteric elements?
These are the elements that can act as a base as well as an acid. If they react with an acid , they behave as a base . And if they react with a base they behave as an acid . Oxides of aluminum and gallium are amphoteric in nature.
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 […]
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 […]
What is aldol Condensation ?
Ald + ol Ald- Aldehyde ; ol – Alcohol. As the name suggests , this is a type of reaction which involve the formation of such a molecule which have “alcohol and aldehyde” functional groups.
What is Perkin reaction ?
Perkin reaction This reaction is used in the synthesis of β-aryl-acrylic acid. This reaction is mostly used for the prepration of cinnamic acid. Coumerin, a flavouring agent is also prepared by this method.
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