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Some substances which are crystalloids under certain conditions can be colloids under the other, e.g. NaCl is a crystalloid in aqueous medium, but when mixed with benzene, it behaves as a colloid. It is the size of the particles of that matter, i.e. the state in which the substance exists. If size lies in range of 1-1000 nm, it is in the colloidal state. So, above statement is true.

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Describe some features of catalysis by zeolites.

Posted by Arica Rose 7 years, 3 months ago

CBSE > Class 12 > Chemistry

3 answers

Aryan Rai 7 years, 3 months ago

no need to mention that. Cheers :)

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Arica Rose 7 years, 3 months ago

Thanks ...dear

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Aryan Rai 7 years, 3 months ago

Some characteristic features are: 1. These are shape selective catalyst or can act as molecular sieves . 2. They have honey-comb like structure. 3. They have specific pore size lying between 260pm to 740pm.

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Why is the dipole moment of chlorobenzene is lower than that of cyclohexyl chloride

Posted by Srivinayak V 7 years, 3 months ago

CBSE > Class 12 > Chemistry

3 answers

Aryan Rai 7 years, 3 months ago

@ Yogita ??

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Aryan Rai 7 years, 3 months ago

In chlorobenzene, the chlorine atom is attached to sp2 hybridised carbon atom. In cyclohexyl chloride, the chlorine atom is attached to sp3 hybridised carbon atom. Hence chlorobenzene is more electronegative than cyclohexyl chloride. Therefore, the density of electrons C-Cl bond at chlorine atom is less in chlorobenzene than cyclohexyl chloride. Due to this polarity of the C-Cl bond decreases and hence dipole moment of chlorobenzene is lower than cyclohexyl chloride.

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Yogita Ingle 7 years, 3 months ago

In chlorobenzene, the chlorine atom is attached to sp²chybridized carbon atom. In cyclohexyl chloride, the chlorine atom is attached to sp³ hybridized carbon atom. Hence chlorobenzene is more electro negative than cyclohexyl chloride. Therefore, the density of electrons C-Cl bond at chlorine atom is less in chlorobenzene than cyclohexyl chloride. Due to this polarity of the C-Cl bond decreases and hence dipole moment of chlorobenzene is lower than cyclohexyl chloride.

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Molar conductivity increases with decrease in concentration why

Posted by Yashveer Chauhan 7 years, 3 months ago

CBSE > Class 12 > Chemistry

1 answers

Yogita Ingle 7 years, 3 months ago

Conductivity changes with the concentration of the electrolyte. The number of ions per unit volume carrying the current decreases on dilution, so conductivity always decreases with decrease in concentration.
However, molar conductivity increases with dilution. This is because conductivity of a solution is the conductance of one unit volume of the solution, but molar conductivity is the conductance of that volume solution containing one mole of electrolyte.
As the total volume of solution containing one mole of electrolyte increases, the decrease in conductivity due to dilution is more than compensated by increase in its volume of solution that contains one mole of the electrolyte.

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What is meant by intrinsic semiconductor

Posted by Rahul Guleria 7 years, 3 months ago

CBSE > Class 12 > Chemistry

1 answers

Yogita Ingle 7 years, 3 months ago

A pure semiconductor, free from impurities is called intrinsic semiconductor

The electrical conductivity of pure semiconductor is called intrinsic conductivity
Structure – Consider pure Germanium and Silicon. Both have 4 valence electrons

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Can I get a blue print of chemistry?

Posted by Riya Jangra 7 years, 3 months ago

CBSE > Class 12 > Chemistry

2 answers

Riya Jangra 7 years, 3 months ago

Can't find it.. please help

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Mansi Sharma 7 years, 3 months ago

Yaa you can see in this app !

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A group 14 element is to be converted into P type semiconductor by doping it with a suitable impurity to which group should juice impurity belong

Posted by Abhishek Guru 7 years, 3 months ago

CBSE > Class 12 > Chemistry

1 answers

Nitika Neb 7 years, 3 months ago

Group 13 element, Arsenic

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What is the relation beetwen ionisation enthalpy and stability of any element

Posted by Pushpendra Pratap Singh 7 years, 4 months ago

CBSE > Class 12 > Chemistry

0 answers

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Why is Vitamin C not stored in our body?

Posted by Aryan Rai 7 years, 4 months ago

CBSE > Class 12 > Chemistry

2 answers

Aryan Rai 7 years, 3 months ago

Thank you @Pushpendra

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Pushpendra Pratap Singh 7 years, 4 months ago

Vitamin C is water soluble so it can remove from our body in form urine

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What happens when white phosphorus is heated with concentrated NaOH solution in an inert atmosphere of CO2 ?

Posted by Nitika Neb 7 years, 4 months ago

CBSE > Class 12 > Chemistry

1 answers

Sneha Bansal 7 years, 3 months ago

Phosphine gas and sodium hypophosphite is formed

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Is froth flotation process is also used for extraction of aluminium

Posted by Khushi Tiwari 7 years, 4 months ago

CBSE > Class 12 > Chemistry

3 answers

Sneha Bansal 7 years, 3 months ago

No ,froth flotation is only for sulphide ores

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Aryan Rai 7 years, 4 months ago

I'm extremely sorry. Yes it is also used for Aluminium extraction.

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Aryan Rai 7 years, 4 months ago

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Ionic solids conduct electricity in molten phase.why??

Posted by Jayashree Maity 7 years, 4 months ago

CBSE > Class 12 > Chemistry

2 answers

Nitika Neb 7 years, 4 months ago

Ionic solids conduct electricity in molten state but not in solid state. ... The ionic solids are insulators in the solid state because the ions are entrapped in fixed places in the crystal lattice & cannot move when electric field is applied.However, in molten state,they become good conductors of electricity.

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Mansi Sharma 7 years, 4 months ago

Coz in molten phase ions dissociate to give the free ions .

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What is more basic aryl amine or ammonia

Posted by Faisal Malik 7 years, 4 months ago

CBSE > Class 12 > Chemistry

1 answers

Nitu Yaduvanshi 7 years, 4 months ago

Ammonium

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Define kraft temperature?

Posted by Narendra Chouhan 7 years, 4 months ago

CBSE > Class 12 > Chemistry

2 answers

Garima Bansal 7 years, 4 months ago

The temp above which micelles formation take place

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Yogita Ingle 7 years, 4 months ago

The Krafft temperature is defined as the minimum temperature at which ionic surfactants, form micells. It depends on the nature of hydrophobic groups and ionic composition of the detergent.

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formula of benedict's solution & fehling's solution.... Plzzz help me...????????

Posted by Tamoghna Roy 7 years, 4 months ago

CBSE > Class 12 > Chemistry

3 answers

Aryan Rai 7 years, 4 months ago

Likewise, Fehling's solution is also a mixture of Fehling solution A and Fehling solution B. where Solution A is Copper Sulphate solution and solution B is sodim potassium titrate. When an aldehyde is treated with Fehling's solution, a red ppt. of Cu2O is obtained which confirms the presence. Ketone don't give this test. Cheers :)

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Aryan Rai 7 years, 4 months ago

Benedict solution has no formula because it's a mixture and not a pure chemical compound.However, it could be prepared by dissolving 100g of anhydrous sodium carbonate,173g of Sodium citrate ,17 g of copper(||) sulphate pentahydrate and the rest distilled water for 1L of solution.

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Tamoghna Roy 7 years, 4 months ago

Urgent...m

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Why Agbr shows both schotty and frenkel defect

Posted by Kt Kt 7 years, 4 months ago

CBSE > Class 12 > Chemistry

3 answers

Aryan Rai 7 years, 4 months ago

Thanks for the explanation.

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Aryan Rai 7 years, 4 months ago

Because Ag+ has a very small size due to which they can occupy interstitial sites once they are removed from lattice point. That's why they show Frenkel defect. And why do they show Schottky defect? I think you know it well. Cheers :)

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Yogita Ingle 7 years, 4 months ago

AgBr shows both Frenkel and Schottky defects because the radius ratio for AgBr is intermediate.

Explaination:

Ions have Schottky defects when their anions and cations are both absent from the crystal lattice.

In AgBr, the Ag⁺ ions and corresponding Br̶̶^‒ ions are absent from the crystal lattice causing Schottky defects.

However, Ag⁺ ions are exceptionally mobile and they have a tendency to move about inside the lattice. So they complement the Schottky defects with Frenkel defects with the Ag⁺ ions trapped in interstitial spaces. Because of the similar size of Ag⁺ ions and Br^‒ ions and the small size of Ag⁺ ions and the fact that Ag⁺ ions have a property to be mobile, both Schottky and Frenkel defects occur.

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Low spin configuration are rarely observed in tetrahedral coordination entity formation .Explain

Posted by Nitika Neb 7 years, 4 months ago

CBSE > Class 12 > Chemistry

1 answers

Aryan Rai 7 years, 4 months ago

In tetrahedral complexes,sp3 hybridization takes place and hence the 3d orbitals are untouched. So unpaired electrons are always there which gives high spin. That's why low spin configuration is not possible. By the way thanks for asking this question, I didn't know the answer so I googled it.

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Write the name of biodegradable polymer used in Orthopaedic devices

Posted by Nitika Neb 7 years, 4 months ago

CBSE > Class 12 > Chemistry

2 answers

Kt Kt 7 years, 4 months ago

Phbv

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Aryan Rai 7 years, 4 months ago

PHBV

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What is intra molecular bond

Posted by Adithyan Karthik 7 years, 4 months ago

CBSE > Class 12 > Chemistry

2 answers

Aryan Rai 7 years, 4 months ago

And intramolecular bond is always greater than that of intermolecular bond.

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Aryan Rai 7 years, 4 months ago

It is the bond between two atoms which leads to the formation of a molecule or compound.

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Covalent compounds

Posted by Adithyan Karthik 7 years, 4 months ago

CBSE > Class 12 > Chemistry

1 answers

Yogita Ingle 7 years, 4 months ago

Covalent compounds are the ones having strong intra-molecular bonds. This is because the atoms within the covalent molecules are very tightly held together. Each molecule is indeed quite separate and the force of attraction between the individual molecules in a covalent compound tends to be weak. Covalent compounds usually have low melting points. An exception to this include molecules of silica and diamonds that have a high melting point.

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White phosphorus is grater than red phosphorus

Posted by Snigdha Tiwari 7 years, 4 months ago

CBSE > Class 12 > Chemistry