CBSE > Class 12 > Chemistry | CBSE Board | Homework Help

There is nothing to have fear of practical..... Only basic will be asked. And u will be able to answer,Have such confidence. And if u will not able to answer. Simply say sorry sir I don't know.

1Thank You

ANSWER

Which effect is observed when h2s gas passed in salt analysis

Posted by Madhvi Rana 6 years, 2 months ago

CBSE > Class 12 > Chemistry

2 answers

Vishal Singh 6 years, 2 months ago

Black ppt is for in case of 2 group

0Thank You

Neha Choudhary 6 years, 2 months ago

Ppt formed in case of 2 group basic radical ppt is black In case of 4 grop ppt is of dull white or puff colour

1Thank You

ANSWER

What is the formula of brown ring????

Posted by Amisha Nanda 6 years, 2 months ago

CBSE > Class 12 > Chemistry

2 answers

Neha Choudhary 6 years, 2 months ago

Not in syllabus

0Thank You

Yogita Ingle 6 years, 2 months ago

A nitrate test is a chemical test used to determine the presence of nitrate ion in solution.

A nitrate test, known as the brown ring test can be performed by adding iron(II) sulfate to the solution, then slowly adding concentrated sulfuric acid and watching for a brown ring on the test tube, which will indicate the presence of the nitrate ion.

The test follows several phases; these have been written as balanced chemical equations:

1: 2 Zn(NO₃)₂+ 2 H₂SO₄ → 2 ZnSO₄ + 4 HNO₃

4 FeSO₄ + 2 H₂SO₄ → 2 Fe₂(SO₄ )₃ + H₂

These two reactions happen simultaneously.

2: 4 HNO₃ → 2 H₂O + 3O₂ + 2 NO

The Nitric Acid decomposes in the intense heat produced by the high concentrate Sulphuric Acid used.

3: 2 Fe₂(SO₄)₃ + 2 H₂ + 4 NO → 4 Fe.NO.SO₄ + 2 H₂SO₄

The Fe.NO.SO₄ forms a brown ring in the middle of the solution produced by the reaction, making it easy to identify the presence of nitrates in the water.

1Thank You

ANSWER

d-block and f- block important h kiya borads ke liye? Aur agr h to kis type ke question asktey h usse?

Posted by Rain Drop 6 years, 2 months ago

CBSE > Class 12 > Chemistry

3 answers

Jd Chouhan 6 years, 2 months ago

Oxidising agent or reducing agent pr

0Thank You

Shivraj Singh Rathore 6 years, 2 months ago

Of 3 marks and 2 marks or may be of one marks but not of 5 marks

1Thank You

Adi Kumar 6 years, 2 months ago

May be a 5 mark questions

1Thank You

ANSWER

Mechanism is important or not in chemistry

Posted by Ishita Modi 6 years, 2 months ago

CBSE > Class 12 > Chemistry

3 answers

Akanksha Verma 6 years, 2 months ago

Ya mechanism is important

0Thank You

Adi Kumar 6 years, 2 months ago

Only two or three important mechanisms are there

2Thank You

Lakshay Bhardwaj 6 years, 2 months ago

Important

1Thank You

ANSWER

Imp Questions for 2019 boards in chemistry

Posted by #Ruhi Singh 6 years, 2 months ago

CBSE > Class 12 > Chemistry

1 answers

Neha Choudhary 6 years, 2 months ago

Ncert important h

1Thank You

ANSWER

Y f2 is more o.agent whereas I2 weak o.agent

Posted by Netra Chettri 6 years, 2 months ago

CBSE > Class 12 > Chemistry

2 answers

Adi Kumar 6 years, 2 months ago

Than iodine

0Thank You

Adi Kumar 6 years, 2 months ago

Fluorine is more electronegative than chlorine

0Thank You

ANSWER

Why is it necessary to remove co when ammonia is obtained by haber's process?

Posted by Jyoti Suhag 6 years, 2 months ago

CBSE > Class 12 > Chemistry

2 answers

Riya Rana 6 years, 2 months ago

Co is poisonous and decreases its yield

0Thank You

Neha Choudhary 6 years, 2 months ago

Becoz CO decreae the production of NH3

0Thank You

ANSWER

What if i got failed in pre board??

Posted by Arshdeep Sekhon 6 years, 2 months ago

CBSE > Class 12 > Chemistry

3 answers

Vinay Gautam 6 years, 2 months ago

Ya start it today dont lose ur hope u cn still score gud

0Thank You

Mohan Singh 6 years, 2 months ago

?????? ya she is right

0Thank You

Kriti Sharma 6 years, 2 months ago

Dont worry ........preboards help you know your level and i think you have realised..... Listen set a target for you i mean know your potential that you will try to get 30+,,,,40+,,,,,50+ in your finals and practice accordingly ok...... Don't leave some important chapters such as optics,,, organic chemistry,,. Focus more on English and physical education..... As these are%tage enhancing subjects.....?

6Thank You

ANSWER

Assertion : Nylon-2-nylon 6 is a biodegradable polymer. Reason : It is a condensation polymer.

Posted by Prashant Patel 6 years, 2 months ago

CBSE > Class 12 > Chemistry

2 answers

Rajat Barwar 6 years, 2 months ago

Assertion and reason both are correct ,but the statement 2 is not correct reason of 1.....

1Thank You

Samir Enstien 6 years, 2 months ago

Oo bhai maaro mujhe maraao

1Thank You

ANSWER

Mechanism of converting ethene to ethanol by hydration

Posted by Yashvi Bhardwaj 6 years, 2 months ago

CBSE > Class 12 > Chemistry

2 answers

Santosh Kumar 6 years, 2 months ago

Ethene gives (HBr in presence) ethylbromide gives (Ag2O in presence) ether gives (H2O&H2SO4) Alcohol

0Thank You

Ã♥╣[-_-]╠♥J ??? 6 years, 2 months ago

Three steps are involved in the mechanism of hydration of ethene to yield ethanol. $$(1)$$ The electrophillic attack of hydronium ion protonates ethene to form carbocation. $$(2)$$ Water (as a nucleophile) attacks carbocation. $$(3)$$ Deprotonation gives ethanol. But i cant show u images of the reactions because on this site image can't uploaded U can see it in the ncert book

0Thank You

ANSWER

Conversion of all:- a. Chloroform to ethyne b. Ethylamine to ethyl alcohol c. Methane to chloroform d. Ethyl alcohol to Ethylamine e. Ethyl alcohol to diether

Posted by Mahroo Naziri 6 years, 2 months ago

CBSE > Class 12 > Chemistry

2 answers

Ritss ?? 6 years, 2 months ago

c. Ch4 + Cl2(excess) gives intermediate ChCl3

0Thank You

Ritss ?? 6 years, 2 months ago

b. C2h5Nh2 in the presence of NaOh +HCl at 0°C gives C2h5Oh

0Thank You

ANSWER

Is halogen acid n mineral acid same❓

Posted by ♥️Bhavika Naik?? 6 years, 2 months ago

CBSE > Class 12 > Chemistry

1 answers

Neha Choudhary 6 years, 2 months ago

0Thank You

ANSWER

Is there is any change in pattern of section A questions .?

Posted by .. Chaudhari 6 years, 2 months ago

CBSE > Class 12 > Chemistry

2 answers

Riya Rana 6 years, 2 months ago

Yess now there will be 20 questions which are one marker.

0Thank You

Neha Choudhary 6 years, 2 months ago

0Thank You

ANSWER

Why should we read chemistry?

Posted by Pavithra A 6 years, 2 months ago

CBSE > Class 12 > Chemistry

2 answers

Vinay Gautam 6 years, 2 months ago

0Thank You

Gaming Zone 6 years, 2 months ago

because its comming in boards??

0Thank You

ANSWER

What is important Ch of chemistry for practical viva board

Posted by Deva T 6 years, 2 months ago

CBSE > Class 12 > Chemistry

4 answers

Anju Yadav 6 years, 2 months ago

Do any chapter which u can completely. U don't have to take tense about that .examiner will simply ask ur chapter. So simple.

0Thank You

.. Chaudhari 6 years, 2 months ago

Organic

0Thank You

Pavithra A 6 years, 2 months ago

Viva itself is a chalange

0Thank You

Kriti Sharma 6 years, 2 months ago

Do organic

0Thank You

ANSWER

Why the sodioum metal brust in watet

Posted by Jhunu Mishra 6 years, 2 months ago

CBSE > Class 12 > Chemistry

1 answers

Riya Rana 6 years, 2 months ago

Extremely reactive

0Thank You

ANSWER

Why methy alcohol is soluble in water

Posted by Aman Singh 6 years, 2 months ago

CBSE > Class 12 > Chemistry

3 answers

Pappy Kumari 6 years, 2 months ago

Because methyl can form hydrogen bonding

0Thank You

Vishal Bohat 6 years, 2 months ago

Because of hydrogen bonding

0Thank You

Gargi Rathore 6 years, 2 months ago

Due to hydrogen bonding

0Thank You

ANSWER

I want mark scheme chapterwise.

Posted by Priyansh Vyas 6 years, 2 months ago

CBSE > Class 12 > Chemistry

0 answers

ANSWER

Can i get the imp. Ques of whole organic chemistry?

Posted by Jaya Kaushik 6 years, 2 months ago

CBSE > Class 12 > Chemistry

1 answers

Kavya Rathore 6 years, 2 months ago

Yes I will

3Thank You

ANSWER

State reason for the following Unlike cr3+ mn2+ fe3+ and the subsequent othr M2+ ions of the 3d serieselements the 4d and 5d series metals genealy donot form stable cationuc species

Posted by Tanisha Kataria 6 years, 2 months ago

CBSE > Class 12 > Chemistry

1 answers

Arya Singh 6 years, 2 months ago

Bcz 3rd ionization enthalpy of 4d and 5d series is high While in the case of Cr+3 and Cr+2, Cr+3 is more stable bcz of fully filled t2g In the case of Fe+3 it has d5 configuration which is half filled And same in the case of Mn+2

0Thank You

ANSWER

Where will the MCQ of chem be asked?

Posted by Gargee K 6 years, 2 months ago

CBSE > Class 12 > Chemistry