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Number of atoms in close packaging = 0.5 mol 1 has 6.022 ×10 23 particles So that, Number of close−packed particles = 0.5 × 6.022 × 1023 = 3.011 × 1023 Number of tetrahedral voids = 2 × number of atoms in close packaging Plug the values we get, Number of tetrahedral voids = 2 × 3.011 × 1023 = 6.022 × 1023 Number of octahedral voids = number of atoms in close packaging So that, Number of octahedral voids = 3.011 × 1023 Total number of voids = Tetrahedral void + octahedral void = 6.022 × 1023 + 3.011 × 1023 = 9.03 × 1023

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While filling up of electrons in the atomic orbitals the 4s orbital is filled before the 3d orbital.........explain with reference to d- and f-block elements

Posted by Nancy Yadav 8 years ago

CBSE > Class 12 > Chemistry

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In first transition 3d series cu has exceptionally positive E°M2+/M value.why?

Posted by Nancy Yadav 8 years ago

CBSE > Class 12 > Chemistry

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Phenol associated in benzene and form a dimer (c6H5oH )2 the freezing point of Sol containing 5 g of phenol into 250 g of c6h6 is lowered by .10 c calculate the degree of associated I n phenol

Posted by Aman Sisodia 8 years ago

CBSE > Class 12 > Chemistry

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what is CMC

Posted by Smriti Pandey 8 years ago

CBSE > Class 12 > Chemistry

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Nisha Beniwal 8 years ago

Critical micellisation conc. Means micelles formation take place above the particular conc.

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why do ether used to prepare the grignard reagent as solvent from alkyl halide and magnesium

Posted by Smriti Pandey 8 years ago

CBSE > Class 12 > Chemistry

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Shorten the answer plz?

Posted by Skrillex Levine 8 years ago

CBSE > Class 12 > Chemistry

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Structure of (HPO3)3

Posted by Saurav Tanwar 8 years ago

CBSE > Class 12 > Chemistry

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Shruti R 8 years ago

O II P=OH /. | O. O /. | / HO =P. __ O _ P=OH II. II O O O.

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Why hypercojucation is permanent effect and mesomeric effectis temporary effect?

Posted by Vivek Tiwari 8 years ago

CBSE > Class 12 > Chemistry

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Define micelles formation???? Plzz comment

Posted by Nisha Beniwal 8 years ago

CBSE > Class 12 > Chemistry

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Define mass percentage

Posted by Sachin Saini 8 years ago

CBSE > Class 12 > Chemistry

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Kritika Trehan 8 years ago

Mass percentage is one way of representing the concentration of an element in a compound or a component in a mixture. Mass percentage is calculated as the mass of a component divided by the total mass of the mixture, multiplied by 100%.

Also Known As: mass percent, (w/w)%

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Role of zn in extraction of silver

Posted by Mohin Nadaf 8 years ago

CBSE > Class 12 > Chemistry

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How can I improve my organic chemistry....specially conversions??

Posted by Apoorve Singh 8 years ago

CBSE > Class 12 > Chemistry

3 answers

Nisha Beniwal 8 years ago

Women men se jadha perfect hoti h ?????

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Vineit Kumar Gupta 8 years ago

Practice makes a man perfect well i cant say about women's ???

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Nikhil Maurya 8 years ago

Yes you can, by practising it...

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Explain Nernest equation

Posted by Aakash Biswas 8 years ago

CBSE > Class 12 > Chemistry

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Method of preparation of carboylic acid from alkyl benzenes description

Posted by Sahiba Samant 8 years ago

CBSE > Class 12 > Chemistry

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(CH3)3C-CHO doesnot undergo aldol condensation .comment.

Posted by Ashish Bhatia 8 years ago

CBSE > Class 12 > Chemistry

2 answers

Summi Farheen 8 years ago

Absence of alpha Hydrogen

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Nisha Beniwal 8 years ago

Bcoz no OH present

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Interstates means

Posted by Vikram Roy 8 years ago

CBSE > Class 12 > Chemistry

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Difference between molarity and molality

Posted by Tarash Baskey 8 years ago

CBSE > Class 12 > Chemistry

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Sia ? 4 years, 6 months ago

The molality of a solution is equal to the moles of solute divided by the mass of solvent in kilograms, while the molarity of a solution is equal to the moles of solute divided by the volume of solution in liters.

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Why cr+2 act as reducing agent but Mn +2 act as oxidising agent though both have same electeonic configuration

Posted by Virendra Aditya 8 years ago

CBSE > Class 12 > Chemistry

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what is the sucrose needs to dissolved 1000g of water in order to decrease the vapour pressure by 30%?

Posted by Pratyush Srivastava 8 years ago

CBSE > Class 12 > Chemistry

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Why Mn+2 compounds are more stable than Fe+2 towards oxidation to their +3 state?

Posted by Chandeliya Rock 8 years ago

CBSE > Class 12 > Chemistry

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Rashi Bari 8 years ago

Due to the the presence of half filled d orbital

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Name a ore having two metal atoms.

Posted by Naveen Garg 8 years ago

CBSE > Class 12 > Chemistry

1 answers

Ritu Sharma 8 years ago

Sulphide ores

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What happens when H3PO3 is heated?

Posted by Madhavi Likhar 8 years ago

CBSE > Class 12 > Chemistry

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Vaishnavi Kumari 8 years ago

When H3PO3 is heated it gives the reaction Please put the heat sign above the arrow mark H3PO3----------> H3PO4 +PH3

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Explain brown ring test??

Posted by Nisha Beniwal 8 years ago

CBSE > Class 12 > Chemistry

1 answers

Naveen Sharma 8 years ago

A common nitrate test, known as the brown ring test can be performed by adding iron(II) sulfate to a solution of a nitrate, then slowly adding concentrated sulfuric acid such that the acid forms a layer below the aqueous solution. A brown ring will form at the junction of the two layers, indicating the presence of the nitrate ion.

The overall reaction is the reduction of the nitrate ion by iron(II) which is oxidised to iron(III) and formation of a nitrosonium complex where nitric oxide is reduced to NO⁻.

{tex}2HNO_3+ 3H_2SO_4 + 6FeSO_4 \to 3Fe_2(SO_4)_3 + 2NO + 4H_2O{/tex}
{tex}[Fe(H_2O)_6]SO_4 + NO = [Fe(H_2O)_5(NO)]SO_4+ H_2O{/tex}

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Why does carboxylic acid doesn't give reaction with carbonyl compounds?

Posted by Sukarn Pahuja 8 years ago

CBSE > Class 12 > Chemistry

1 answers

Naveen Sharma 8 years ago

The carbonyl carbon in ketones and aldehydes is more electrophilic than in carboxylic acids.This is because the lone pairs on oxygen atom attached to hydrogen atom in the -COOH group are involved in resonance thereby making the carbon atom less electrophilic.

Hence, carboxylic acids do not give characteristic reaction of carbonyl group.

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Very important 10structure in organic chemistry

Posted by Suyash Dwivedi 8 years ago

CBSE > Class 12 > Chemistry

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Which is More coagulated positive charged NaCl or BaSO4

Posted by Shalik Dubey 8 years ago

CBSE > Class 12 > Chemistry

1 answers

Nancy Yadav 8 years ago

Baso4 bcoz it has more neg chrg

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Why zinc oxide which is white in color does become yellow heating?

Posted by Priyanka Choudhary 8 years ago

CBSE > Class 12 > Chemistry

2 answers

Virendra Aditya 8 years ago

ZnO turns yellow on heating due to non stoichiometric defact i.e. metal excess defact. This defact is caused by extra cations in the interstitial site . On heating oxygen escapes the lattice leaving behind the electron which give ZnO YELLOW COLOUR

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Nisha Beniwal 8 years ago

Due to the presence of f-centre

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