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What is the chapterwise distribution of marks of all chapters in chemistry

Posted by Monalisa Jena 7 years, 3 months ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

Ketones are less reactive than aldehydes in the nucleophillic addition rxn ? why

Posted by Avinaw Bhardwaj 7 years, 3 months ago

CBSE > Class 12 > Chemistry

1 answers

Yogita Ingle 7 years, 3 months ago

Aldehydes are more reactive than ketones towards nucleophilic addition reactions due to the following factors:
1. Aldehydes are less sterically hindered as compared to ketones.
2. Aldehydes are more reactive as compared to ketones due to factors like hyperconjugation.
3. Carbonyl group in an aldehyde is more polar than the carbonyl group of ketones.

ANSWER

Preperation of phenol

Posted by S M 7 years, 3 months ago

CBSE > Class 12 > Chemistry

2 answers

Gaurav Seth 7 years, 3 months ago

1) Preparation of Phenols from Haloarenes

Chlorobenzene is an example of haloarenes. We can obtain chlorobenzene by the monosubstitution of a benzene ring. When chlorobenzene fuses with sodium hydroxide at 623K and 320 atm, we obtain sodium phenoxide. Finally, sodium phenoxide on acidification gives phenols.

2) Preparation of Phenols from Benzene Sulphonic Acid

We can obtain Benzenesulphonic from benzene by reacting it with oleum. Benzenesulphonic acid, thus formed, is treated with molten sodium hydroxide at high temperature. This process leads to the formation of sodium phenoxide. Finally, sodium phenoxide on acidification gives phenols.

3) Preparation of Phenols from Diazonium Salts

When we treat an aromatic primary amine with nitrous (NaNO2 + HCl) acid at 273 – 278 K, we can easily obtain diazonium salts. These diazonium salts are highly reactive in nature. Upon warming with water, these diazonium salts finally hydrolyse to phenols. We can also obtain phenols from diazonium salts by treating it with dilute acids.

4) Preparation of Phenols from Cumene

Cumene is an organic compound that we can obtain by the Friedel-Crafts alkylation of benzene with propylene. Upon oxidation of cumene (isopropylbenzene) in presence of air, we obtain cumene hydroperoxide.

Upon further treatment of cumene hydroperoxide with dilute acid, we get the phenols. We also produce acetone as one of the by-products of this reaction in large quantities. Hence, phenols prepared by these methods need purifications.

S M 7 years, 3 months ago

Best method

ANSWER

What happens when glucose react with HNo3

Posted by Nitika Neb 5 years, 11 months ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

What is the role of depressant in froth flotation process?

Posted by Nitika Neb 7 years, 3 months ago

CBSE > Class 12 > Chemistry

1 answers

Shubham Taneja 7 years, 3 months ago

Depressant is used to seperate two sulphide ores. For eg. If we take zns and pbs depressant will be NACN then it prevents zns from coming froth but allows pbs to come with froath.

ANSWER

Explain the amphoteric behaviour of amino acids?

Posted by Nitika Neb 7 years, 3 months ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

How to do organic effectivly to get good marks in the exams

Posted by Tarun Gulia 7 years, 3 months ago

CBSE > Class 12 > Chemistry

2 answers

Navya Singh 7 years, 3 months ago

Ncert is best for organic ..just do it by understanding reactions nd name rxns are most important

Mansi Sharma 7 years, 3 months ago

First of all u should learn all the name rxn's and others nd all the concepts in ncert book . Then all the conversions ,distinguishes .......u should very well known about that . These will perfectly Increase ur marks in organic .

ANSWER

How to deal with IUPAC naming of coordination compounds??

Posted by Mansi Sharma 7 years, 3 months ago

CBSE > Class 12 > Chemistry

2 answers

Mansi Sharma 7 years, 3 months ago

IUPAC of coordination is much easier then organic

Hritik Jha 7 years, 3 months ago

Follow some basic rule and for sure you would be able to name them just you have to stydy the types of it

ANSWER

Why crystalline solids anisotropic?

Posted by Saurav Verma 7 years, 3 months ago

CBSE > Class 12 > Chemistry

3 answers

Ashish Soni 7 years, 3 months ago

Because their physical property like temperature, refractive index e.t.c are different in different direction.

Divanshi Bhardwaj 7 years, 3 months ago

They are anisotropic because some of the property like refrective index have different value for different direction Shortcut to learn ( D.D for crystaline and for anisotropic same value for different direction S.D )

Navya Singh 7 years, 3 months ago

Because they show different physical properties like refractive index etc. in different directions

ANSWER

Why nitrogen is not reactive under normal condition

Posted by Asheesh Yadav 7 years, 3 months ago

CBSE > Class 12 > Chemistry

1 answers

Yogita Ingle 7 years, 3 months ago

Nitrogen is inert molecule because in nitrogen there exist a triple bond betwwn the two nitrogen atoms.
This triple bond constituted of one sigma and two pi bonds i.e.
P_x - P_x overlap to form sigma bond.
Py-P_y and P_z - P_z overlaps to form pi bond.
The intermolecular forces in this are weak Van der Walls forces. So, the diatomic molecules exist freely.Because of the triple bond,the bond energy is very high.The bond dissociation energy of nitrogen is 945.4 kJ/mol.Due to this high bond dissociation energy, nitrogen is apparently inactive under normal conditions.This is why nitrogen is unreactive gas.

ANSWER

Everyone give different views . Which is best any sampler paper or any book for good score. I confiused . Please help me to find which is best

Posted by Harshit Pratap Singh 7 years, 3 months ago

CBSE > Class 12 > Chemistry

5 answers

Mansi Sharma 7 years, 3 months ago

Arihant chapterwise are the best my di also scored very well with it and i am also preffrring it it have variety of questions that can be arised from any chapter i really suggest that u should go through arihant ....best book

Navya Singh 7 years, 3 months ago

You can prefer xam idea or oswal sample paper

Saumya Agrawal 7 years, 3 months ago

I mean 5 year question papers ...

Saumya Agrawal 7 years, 3 months ago

What i believe is that first you must complete ncert solutions with full attention and after that you should solve 5 years sample papers and after that any book you can use okkk......

Rajat Dhull 7 years, 3 months ago

Each book is good follow anyone but read completly.

ANSWER

what is the iupac name of {Ag{NH3)2}{Ag(CN)2}

Posted by Ujjwal Dhaniya 7 years, 3 months ago

CBSE > Class 12 > Chemistry

2 answers

Aryan Rai 7 years, 3 months ago

dicyanidosilver (||)

Asheesh Yadav 7 years, 3 months ago

Diaminesilver

ANSWER

Plz tell me from where i get last years question paper for my preparation or suggest a book name in which only lasts year paper is there.

Posted by Garima Chauhan 7 years, 3 months ago

CBSE > Class 12 > Chemistry

5 answers

Garima Chauhan 7 years, 3 months ago

Ok thanks

Aryan Rai 7 years, 3 months ago

Hope this will be helpful to you too :)

Aryan Rai 7 years, 3 months ago

I had done OSWAAL SOLVED PAPERS in class 10 and I'm going with it also in class 12. I think OSWAAL SOLVED PAPERS is better than CBSE 15 SAMPLE QUESTION PAPERS.

Garima Chauhan 7 years, 3 months ago

Hey Tell me which u prefer

Aryan Rai 7 years, 3 months ago

Hey.. There are two types of books available in market of OSWAAL. One is OSWAAL SOLVED PAPERS where you get the notes of every chapter and at end of every chapter there is a lot of questions for practice along with marking schemes issued by the board. The questions consist of a set of levels like Level-1,2 and HOTS. Also it is mentioned that when was that particular question asked in the board. And the other one is CBSE 15 SAMPLE QUESTION PAPERS it is also from OSWAAL. But in that only samples paper are given along with a short note on every chapter and the hints to the questions are also given. So choose what you want form these two.

ANSWER

20gm Noah with 200gm water calculate (m). Molality

Posted by Abhishek Yadav 7 years, 3 months ago

CBSE > Class 12 > Chemistry

2 answers

Aryan Rai 7 years, 3 months ago

I mean 2.5m and you should write the formula correctly. It's not Noah, it's NaOH

Aryan Rai 7 years, 3 months ago

2.5M

ANSWER

Why are the aquatic species more comfortable in cold water in comparison to warm water?

Posted by Rajit Sharma 7 years, 3 months ago

CBSE > Class 12 > Chemistry

1 answers

Manan Bedi 7 years, 3 months ago

Bcoz oxygen is more soluble in cold water

ANSWER

How would you convert ethanol to ethene?

Posted by Shivanand Babu 7 years, 3 months ago

CBSE > Class 12 > Chemistry

2 answers

Yogita Ingle 7 years, 3 months ago

When dehydration of ethanol is carried out at a higher temperature (443 K), ethene is formed. The following chemical reaction takes place.

Gaurav Seth 7 years, 3 months ago

When dehydration of ethanol is carried out at a higher temperature (443 K), ethene is formed. The following chemical reaction takes place.

ANSWER

What is the value of tetrahedral void?

Posted by Pulkit Tomar 7 years, 3 months ago

CBSE > Class 12 > Chemistry

1 answers

Yogita Ingle 7 years, 3 months ago

Take a unit cell of ccp or fcc lattice divide into eight small cubes with each small cube having atoms at alternate corners.
Thus, each small cube has 4 atoms that on joining to each other make a regular tetrahedron.
Thus, there is one tetrahedral void in each small cube and eight tetrahedral voids in total.
Each of the eight small cubes have one void in one unit cell of ccp
ccp structure has 4 atoms per unit cell. Thus, the number of tetrahedral voids is twice the number of atoms.

ANSWER

What is Dow's process?

Posted by Batul Ali Bohra 7 years, 3 months ago

CBSE > Class 12 > Chemistry

2 answers

Yogita Ingle 7 years, 3 months ago

Dow's process is the method of formation of phenol from chlorobenzene, by treating chlorobenzene with Sodium hydroxide at 673 K.

Priyanka Singh 7 years, 3 months ago

Chloro benzene +NaOH -----> sodium phenoxide (benzene with ONa in 1st position) --------> phenol

ANSWER

Why alcohol are less acidic than water??

Posted by Vipin Gautam 7 years, 3 months ago

CBSE > Class 12 > Chemistry

1 answers

Priyanka Singh 7 years, 3 months ago

Because alcohol is less polar than water

ANSWER

Hell - volhard zelibsky reaction

Posted by Manoj Boura 7 years, 3 months ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

What is benzylic halides

Posted by Ayush Katiyar 7 years, 3 months ago

CBSE > Class 12 > Chemistry

1 answers

Krishna Garg 7 years, 3 months ago

These are the compounds in which the halogen atom is bonded to a sp3-hybridised carbon atom next to an aromatic ring . Ex.Toluene.☺

ANSWER

Structure and bond angle of P4O10

Posted by Ashu Patel 7 years, 3 months ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

An element X with atomic mass 60g/mol has density of 6.23g cm-3

Posted by Sharul Sharma 7 years, 3 months ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

From where I should download solution of sample paper of chemistry

Posted by Aman Raj 7 years, 3 months ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

[Fe(CO)5] Write shape of this complex ion.

Posted by Sãñjü Dïdêl 7 years, 3 months ago

CBSE > Class 12 > Chemistry

1 answers

Arti Vishwakarma 7 years, 3 months ago

trigonal bipyramidal

ANSWER

What is synergic effect for metal ion.

Posted by Sãñjü Dïdêl 7 years, 3 months ago

CBSE > Class 12 > Chemistry

1 answers

Gautam Mali 7 years, 3 months ago

Two complementary metal ions were used to enhance the performance of electrode materials. The specific capacitance of the electroactive materials was continuously improved by increasing the nickel ion content, and the electric conductivity was also enhanced when the cobalt ion was varied

ANSWER

Explain the mechanism of electrophilic substitution of aryl halides with example

Posted by Saba Parvez 7 years, 3 months ago

CBSE > Class 12 > Chemistry

1 answers

Priyanka Singh 7 years, 3 months ago

The mechanism of electrophillic substitution of aryl halides goes in accordance to SN1 reaction,there is a foramation of cabocation which gets stabilised through resonance.

ANSWER

What is the difference b/w lanthanoid contraction and decresae in radii of period 3,4,5

Posted by Mohit Yadav 7 years, 3 months ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

asparin is used in prevention of heart attack why

Posted by Deepak Meena 7 years, 3 months ago

CBSE > Class 12 > Chemistry

4 answers

Priyanka Singh 7 years, 3 months ago

Asprin is an blood dilutor,it dilutes the blood and makes it thinner to reduce the stress on hreat arteries and makes it easier for the heart to pump blood

Muskan Thakur 7 years, 3 months ago

asprin is the type of drug which makes the blood thick so that it can easily circulate in our body which helps to prevent heart attacks

Manish Yadav 7 years, 3 months ago

Asprin makes the blood thick i.e. blood can eaisly pass through blocked nerves which help in preventing heart attack

Yogita Ingle 7 years, 3 months ago

When we have a heart attack, it's because one of the coronary arteries (which provide blood to the heart, has developed a clot that obstructs the flow of blood and oxygen to the heart. Aspirin works by interfering with your blood's clotting action and it helps in thinning of blood.

ANSWER

What is lanthanoid contraction

Posted by Alok Shrivastava 7 years, 3 months ago

CBSE > Class 12 > Chemistry

2 answers

Aryan Rai 7 years, 3 months ago

Due to which all the Lanthanoid elements show similar chemical property and it becomes difficult to distinguish b/w them.

Anand Satyarthi 7 years, 3 months ago

When we going on the right side in the lanthniod 14 group element atomic and ionic radii decreases with atomic number increase it phenomena called lanthniod construction

ANSWER

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