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Why there is a irregular variation of ionisation enthalpies in the first series of transition.... Elements

Posted by Àñshul Shärmã 7 years ago

CBSE > Class 12 > Chemistry

1 answers

Somya Duhan 7 years ago

Due to variance in no. Of valence electrons.

ANSWER

Conductivity of two electrolytic solutions of 0.1 M concentration of the substances A and B are 9.2 × 10 –3 and 4.7 ×10 –4 S cm –1, which one of these offer less resistance for the flow of current and which one is a stronger electrolyte?

Posted by Akshat Pegwar 7 years ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

Solute and solvent difference

Posted by Cherina Haorokcham 7 years ago

CBSE > Class 12 > Chemistry

2 answers

Shashikant Kumar 7 years ago

Which is present in lesser amount in solution is called solute whereas which is present in larger amount in solution is called solvent.

Sanu Singh 7 years ago

Solute is a substance that you add to a solvent to make a solution. For example: you mix salt into water here, salt is the solute and water is the solvent. The substance taken in major quantity is solvent and the substance taken in minor amount is called solute. What you add is solute and in the substance you add to it is solvent.

ANSWER

Atom

Posted by Harishkumar Khundrakpam 7 years ago

CBSE > Class 12 > Chemistry

1 answers

Nitika Neb 7 years ago

An atom is the smallest unit of matter that has the properties of an element. It is composed of a dense core called the nucleus and a series of outer shells occupied by orbiting electrons. The nucleus, composed of protons and neutrons, is at the center of an atom.

ANSWER

What is neo and iso in nomenclature of organic compounds

Posted by Krishnendu S K 7 years ago

CBSE > Class 12 > Chemistry

1 answers

Yogita Ingle 7 years ago

The prefix "iso" is used when all carbons except one form a continuous chain. This one carbon is part of an isopropyl group at the end of the chain.
"Iso" can also indicate that the molecule is an constitutional isomer of another molecule with a common (or trivial) name.

ANSWER

What is fuel cell?

Posted by Naresh Tudu 7 years ago

CBSE > Class 12 > Chemistry

3 answers

Mansi Sharma 7 years ago

It consists of electrolyte and 2 electrodes .

Yogita Ingle 7 years ago

In this kind of cell the chemical energyof fossil fuels like coal,gas or oil is initially used to convertwater into high pressure steam and is used to run a turbine to generate.
Hydrogen and oxygenare bubbled using porous carbon electrodes into concentrated aqueoussodium hydroxide solution.
Finely splitted platinum orpalladium metal are added to the electrodes for increasing the rateof electrode reactions .

Mansi Sharma 7 years ago

A device which converts a chemical energy of fuel directly into electricity (usually hydrogen )

ANSWER

Copper crystallize with fcc unit cell. If the radius of copper atom is 127.8pm, calculate the density of copper metal (Atomic mass of Cu=63.55 u and NA=6.023*10 power 23 Mol)

Posted by Khelan (Khellu) 7 years ago

CBSE > Class 12 > Chemistry

2 answers

Faisal Ahmad 7 years ago

Given, Z=4 (fcc) M=63.55 Na=6.022×10^23 r=127.8pm Where, a= 2√2r a= 2×1.414×127.8 a= 361.4pm a= 361.4×10^-10 a= 3.614×10^-8 So, Density= Z×M/a^3×Na Density, = 4×63.55/(3.614×10^-8)^3×6.022×10^23 =8.94 gm/cm^3

Faisal Ahmad 7 years ago

8.94 gm/cm^3

ANSWER

Although cr+6 has no d electron but still colored? How?

Posted by Somya Duhan 7 years ago

CBSE > Class 12 > Chemistry

1 answers

Mohit Sepat 7 years ago

If any element have no electron in valence shell then it will not be coloured

ANSWER

A first order reaction takes 30 minutes for 50% completion. Calculate the time required for 90%completion of this reaction. (log2=0.3010)

Posted by Khelan (Khellu) 7 years ago

CBSE > Class 12 > Chemistry

1 answers

Mohit Sepat 7 years ago

Double of this

ANSWER

Buffer solution

Posted by Manju Kushwaha 7 years ago

CBSE > Class 12 > Chemistry

1 answers

Nitika Neb 7 years ago

Buffers are solutions that resist change in pH on dilution or on the addition of small amounts of acids or alkali.

ANSWER

What is the effect of change in pH on K2Cr2O7 solution

Posted by Sourabh Singh 7 years ago

CBSE > Class 12 > Chemistry

1 answers

Yogita Ingle 7 years ago

The potassium dichromate (K₂Cr₂O₇ ), solution contain dichromate ( Cr₂O₇^2- ion . The ion is less basic and so increase in pH increase in the basicity of the compound.
In simple words, by decreasing hydrogen ion concentration the dichromate ion is converted to chromate ion or vice versa.

ANSWER

Write steps in the preparation of K2Cr2O7 from chromite ore?

Posted by Sourabh Singh 7 years ago

CBSE > Class 12 > Chemistry

1 answers

Yogita Ingle 7 years ago

The preparation of potassium dichromate from chromite involves the following main steps:
(i) The chromate ore is finely ground and heated strongly with molten alkali in the presence of air.
2FeCr₂O₇+ 8NaOH + 7/2 O₂→ 4Na₂Cr₂O₇+ Fe₂O₃ + 4H₂O
(ii) The solution of sodium chromate is filtered and acidified with dilute sulphuric acid so that sodium dichromate is obtained.
2FeCr₂O₇ + H₃SO₄ → Na₂Cr₂O₇ + Na₂SO₄ + H₂O
(iii) A calculated quantity of potassium chloride is added to a hot concentrated solution of sodium dichromate. Potassium dichromate is less soluble therefore it crystallizes out first.
Na₂Cr₂O₇ + 2HCl → K₂Cr₂O₇ + 2NaCl

ANSWER

Where can i find ladoratory manual?

Posted by Srishti Khanna 7 years ago

CBSE > Class 12 > Chemistry

1 answers

Nitika Neb 7 years ago

It is given at last in practical file

ANSWER

Give one chemical test to distinguish b/w ethylamine and aniline or aniline and benzylamine

Posted by Garima Chauhan 7 years ago

CBSE > Class 12 > Chemistry

2 answers

O Singh 7 years ago

Azo dye test given by aniline

Shashikant Kumar 7 years ago

Ethylamine & aniline can be distinguished from each other by the azo dye test. Aniline & benzylamine can be dishtinguished by their reaction with the help of nitrous acid which is prepared from a mineral acid & sodium nitrite.On the other hand aniline reacts with HNO2 at low temp. to form stable diazonium salt.

ANSWER

How to learn chemistry???????? I understand all the concepts , equations , reasoning based questions nd all equations but i can't learn all these things .......

Posted by Mansi Sharma 7 years ago

CBSE > Class 12 > Chemistry

3 answers

Aryan Rai 7 years ago

Practice daily not in the form of reading but in the form of writing. I think it would help you.

Mansi Sharma 7 years ago

I have already learned all the reactions that is not the mattter how to keep in mind is the prblm dude!

Shashikant Kumar 7 years ago

Now you have not much time.so you try to learn only important naming reaction nd terms .learn start now with enjoyment.Best of luck for board exam.

ANSWER

Why rate of reaction double on 10 celcius rise in temperature

Posted by Himanshu Sharma 7 years ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

???What is chelation ❓???? Please answer in simple words?

Posted by Yo Yo Honey Singh ? 7 years ago

CBSE > Class 12 > Chemistry

1 answers

Nikky Saxena 7 years ago

The property of an ligand to form ring complex with metal ion is known as chelation

ANSWER

What is de icing agent ?

Posted by Gud Luck ? 7 years ago

CBSE > Class 12 > Chemistry

1 answers

Faisal Ahmad 7 years ago

Those substance Which lowers the freezing point

ANSWER

Convert methyl amine and ethyl amine

Posted by First Name Last Name 7 years ago

CBSE > Class 12 > Chemistry

1 answers

Gud Luck ? 7 years ago

Methyl amine is treated with HNO2 and we get methanol which is further treated with Cl2 to get methyl chloride whuch is further treated with KCN to get ethylisocyanide nd then it is reduced with reducing agent LiAlH4 to get ethyl amine

ANSWER

Differntiate between inversion and retention..(three points atleast)

Posted by Nikita Choudhary 7 years ago

CBSE > Class 12 > Chemistry

1 answers

Yogita Ingle 7 years ago

Retention: Retention refers to the process wherein the configuration of the molecule is retained after the reaction. Therefore the product molecule has the same configuration as the reactant molecule.

Inversion: Inversion refers to the process wherein the configuration of the molecules is reversed during the course of the reaction. Therefore, the product is of the opposite enantiomeric form as compared to the reactant.

ANSWER

I want a full chart of chemical distinguish of organic compound

Posted by Kunal Kumar 7 years ago

CBSE > Class 12 > Chemistry

1 answers

Somya Duhan 7 years ago

It is in appendix 2 or 3 of pardeep book 2nd semester

ANSWER

Structure of di- sec butyl ketone

Posted by Rajat Negi 7 years ago

CBSE > Class 12 > Chemistry

2 answers

Mohit ..... 7 years ago

How did u do that?

Yogita Ingle 7 years ago

Following are the structure of di sec butyl ketone

ANSWER

I am facing problem with remembering the reactions of organic chemistry. So can U help me to short out this problem guys ?

Posted by Saurabh Yadav 7 years ago

CBSE > Class 12 > Chemistry

5 answers

Gyandeep Srivastava 7 years ago

Make our mind and eyes happy. .. yellow colur

Gyandeep Srivastava 7 years ago

yellow colour is most liked by our eyes

Navya Singh 7 years ago

It requires regular practice

Somya Duhan 7 years ago

Why yellow sheet?

Gyandeep Srivastava 7 years ago

write reactions on a yellow sheet and stick it in front of bed

ANSWER

Best way to study chemistry who knows answer it

Posted by Rupas Chettri 7 years ago

CBSE > Class 12 > Chemistry

4 answers

Nitika Neb 7 years ago

Read the NCERT thoroughly and do ten year papers

Navya Singh 7 years ago

I also want help in chemistry. ..plz tell me

Aryan Rai 7 years ago

In simple language bhot रटना है।

Sneha Chaudhari 7 years ago

just go through the chp n try to learn the notes

ANSWER

Difference between reagents nd catalyst?

Posted by Navya Singh 7 years ago

CBSE > Class 12 > Chemistry

2 answers

Rupas Chettri 7 years ago

In simple regent help to do camical reaction but catalyst incress the rate or some time decress the rate of reaction..?

Nitika Neb 7 years ago

The terms reactant and reagent are often used interchangeably—however, a reactant is more specifically a substance consumed in the course of a chemical reaction. Solvents, though involved in the reaction, are usually not called reactants. Similarly, catalysts are not consumed by the reaction, so they are not reactants.

ANSWER

Colloide

Posted by Riya Ghaloth 7 years ago

CBSE > Class 12 > Chemistry

1 answers

Nitika Neb 7 years ago

homogeneous non-crystalline substance consisting of large molecules or ultramicroscopic particles of one substance dispersed through a second substance. Colloids include gels, sols, and emulsions; the particles do not settle, and cannot be separated out by ordinary filtering or centrifuging like those in a suspension.

ANSWER

Alum is used in cleaning water .Explain.

Posted by Adity Kumari 7 years ago

CBSE > Class 12 > Chemistry

1 answers

Yogita Ingle 7 years ago

As alum coagulates the colloidal properties present in water, so these impurities settle down and removed by filtration.
The increased size as well as the lack of repelling charges cause the alum particles to settle down at the bottom or rise up and float in the water.
After the particles are neutralized, they clump together because of the London Dispersion Force which are part of the Van der Waals forces. Basically, weak intermolecular force arising from quantum-induced instantaneous polarization multipoles in molecules causes even nonpolar particles to attract each other due to the correlated movements of the electrons in interacting molecules. Then they settles down.

ANSWER

Convert acetic acid to acetone

Posted by Shreya Yadav 7 years ago

CBSE > Class 12 > Chemistry

3 answers

Aniket Yadav 5 years, 11 months ago

By treating it with CH3-Mg-cl and then hydrolysing it

Yogita Ingle 7 years ago

Acetic acid is converted to acetone with the help of alkyl cadium reagent
Step I
CH₃COOH {tex}\xrightarrow{\;SOCl_2}{/tex} CH₃COCl
Step II
CH₃COCl {tex}\xrightarrow{\;(CH_3)_2Cd}{/tex} CH₃COCH₃

Mitali Sharma 7 years ago

Ni/H²

ANSWER

What are confirmation and configuration isomers ?

Posted by Navya Singh 7 years ago

CBSE > Class 12 > Chemistry

4 answers

Gud Luck ? 7 years ago

What is this @chetna vats ?u should answer the question properly

Navya Singh 7 years ago

It is from haloalkane and haloarenes. .

Somya Duhan 7 years ago

Which chapter? Is it important for board.

Yogita Ingle 7 years ago

Configuration is arrangement of atom in three dimensional space around the molecule. Here there is no free rotation of atom usually we use configuration in optical isomerism and conformation is the one which allows free rotation of single bond with in the molecule and we use conformation to represent the biomolecule structure.

ANSWER

To find one acidic and one basic radical in the given salt

Posted by Ashish Ranjan 7 years ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

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