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Elastomer

Posted by Suyash Tripathi 6 years, 10 months ago

CBSE > Class 12 > Chemistry

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Important chapters/topics for final exam

Posted by Amit Kumar 6 years, 10 months ago

CBSE > Class 12 > Chemistry

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How many dichloro subustution product are possible for isobutane ?give their structure and IUPAC name

Posted by Ravi Kumar 6 years, 10 months ago

CBSE > Class 12 > Chemistry

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Very important chapters which I learn. I can get good marks

Posted by Shashwat Nigam 6 years, 10 months ago

CBSE > Class 12 > Chemistry

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Calculate the freezing point of solution when 2g of Na2So4 (M=142g mol^-1) was dissolved in 50g of water, assuming Na2So4 undergoes complete ionization (Kf for water =1.86k kg mol^-1).

Posted by Rajam 1969 6 years, 10 months ago

CBSE > Class 12 > Chemistry

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Calculate the freezing point of the solution when 31g of ethylene glycol (C2 H6 O2) is dissolved in 500g of water (Kf for water=1.86k kg mol^-1).

Posted by Rajam 1969 6 years, 10 months ago

CBSE > Class 12 > Chemistry

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Calculate the freezing point of an aqueous solution containing 10.5g of magnesium bromide in 200g of water, assuming complete dissociation of magnesium bromide. (Molar mass of magnesium bromide =184g mol^-1,kf for water=1.86k kg mol^-1).

Posted by Rajam 1969 6 years, 10 months ago

CBSE > Class 12 > Chemistry

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Write the IUPAC name of compound(pt cl (NH2 CH3) (NH3) 2)cl

Posted by Saroj Murra 6 years, 10 months ago

CBSE > Class 12 > Chemistry

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Why do zr and Hi exhibit similar properties

Posted by Saroj Murra 6 years, 10 months ago

CBSE > Class 12 > Chemistry

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importance of osmosis

Posted by Sahruf Khan 6 years, 10 months ago

CBSE > Class 12 > Chemistry

1 answers

Akshat Singh 6 years, 10 months ago

Ro's and fishes during their breeding season

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An element has bcc structure and has edge length 290pm. If the density of the element is 6.8g/cm^3. Calculate the number of atoms in 200g of the element.

Posted by Swastik Kasera 6 years, 10 months ago

CBSE > Class 12 > Chemistry

2 answers

Swastik Kasera 6 years, 9 months ago

Please also give me the answer because it does not match with my solution.?

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Neha ?? 6 years, 10 months ago

Given Z=2. a=290×10^-10cm. M=200g. d=6.8g/cm^3. Na=? Use formula d=Z×M/a^3×Na.

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What are the difference b/w nucleoside or nucleotide

Posted by Sonal Sonal 6 years, 10 months ago

CBSE > Class 12 > Chemistry

3 answers

Prajjawal Sharma 6 years, 10 months ago

when a pentose sugar molecule makes glycosidic linkage with the nitrgenous base then it forms a nucleoside and when nucleoside form phosphoester bond with a phosphate molexule it forms nucleotide whose repeated units form polynucleotide

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Sonal Sonal 6 years, 10 months ago

Aache se define kro plzz

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Prajjawal Sharma 6 years, 10 months ago

Difference of phosphate group

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Explain peptide linkage

Posted by Sonal Sonal 6 years, 10 months ago

CBSE > Class 12 > Chemistry

1 answers

Prajjawal Sharma 6 years, 10 months ago

It is a condensation bond formed between amino acid molecule between nh2 and cooh group

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Systematic analysis group 4

Posted by P V 6 years, 10 months ago

CBSE > Class 12 > Chemistry

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Why does the rate of a reaction not remain constant throughout the reaction process?

Posted by Ankur Kumar 6 years, 10 months ago

CBSE > Class 12 > Chemistry

1 answers

Sonal Sonal 6 years, 10 months ago

Because rate of a reaction is directly proporrional to reduction of reactant ar formation of product

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Numerical carry mxm marks ??

Posted by Sangeeta Nara 6 years, 10 months ago

CBSE > Class 12 > Chemistry

3 answers

Dev Pratap Singh 6 years, 10 months ago

10 to 15 marks

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Dharshika As 6 years, 10 months ago

3marks or 5 marks

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Dharshika As 6 years, 10 months ago

3 marks of 5 marks

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Why oxygen act as a gas and sulphur as liquid

Posted by Sanjays Suresh 6 years, 10 months ago

CBSE > Class 12 > Chemistry

2 answers

Sonal Sonal 6 years, 10 months ago

Because of there atomicity

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Sayeda Iram Ateeq 6 years, 10 months ago

The axygen molecules are held together by weak vander waal's forces because of the small size and high electronegativity of oxygen. Sulphur shows catenation and the molecule is made up of eight atoms with strong intramolecular attractive force. Hence, sulphur exists as solid and oxygen as gas.

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what is f centre

Posted by Hunny Rawal 6 years, 10 months ago

CBSE > Class 12 > Chemistry

2 answers

Sonal Sonal 6 years, 10 months ago

The vacant anioinic vacancy where eletron get come ar called f centre

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Gudiya Yadav 6 years, 10 months ago

The position in the crystal where an electron is tapped known as f-centre

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I there! Can I pls get CHEMISTRY blue print latest one?

Posted by Mehak Sharma 6 years, 10 months ago

CBSE > Class 12 > Chemistry

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Why are hydrophobic sols eaisly coagulated.

Posted by Susheela Bhadoriya 6 years, 10 months ago

CBSE > Class 12 > Chemistry

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Name the deficiency diseases result in from lack of vitamin A and vitamin E in the diet

Posted by Prince Pal 6 years, 10 months ago

CBSE > Class 12 > Chemistry

1 answers

Ashish Shrivas 6 years, 10 months ago

A- night blindness E- reproductive failure

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What is the cause of feeling of depression in human being name a drug which can be useful in treating depression

Posted by Suyash Tripathi 6 years, 10 months ago

CBSE > Class 12 > Chemistry

3 answers

Shivam Jaiswal 6 years, 10 months ago

Cause is non adrenaline or we can say less amt of adrenaline Antidepressant drugs are used to cure it

1Thank You

Ash Thunderbird ✔ 6 years, 10 months ago

Noradrenaline is a neurotransmitter which plays an important role in mood changes. If a person has low level of noradrenaline, then the message transfer process becomes slow and the person suffers from depression. Iproniazid is a drug used to counteract the effect of depression.

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Sunil Dutt 6 years, 10 months ago

equanil drug

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What are limited spectrum antibiotic give one example

Posted by Suyash Tripathi 6 years, 10 months ago

CBSE > Class 12 > Chemistry

2 answers

Ash Thunderbird ✔ 6 years, 10 months ago

Iram Ateeq, I think what you said is about narrow spectrum antibiotics. If an antibiotic is effective against a single microorganism, it is referred to as limited spectrum antibiotic. Example: Penicillin G

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Sayeda Iram Ateeq 6 years, 10 months ago

The antibiotics which kills or inhibits a wide range of gram positive or gram negative bacteria are called limited spectrum antibiotics. e.g., Penicillin-G.

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Can i use black pen to write answer in cbse board exam

Posted by Akshay Kumar 6 years, 10 months ago

CBSE > Class 12 > Chemistry

2 answers

Dev Pratap Singh 6 years, 10 months ago

Only blue pens are allowed

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Neha ?? 6 years, 10 months ago

U can only use it to write the question no. Other wise use blue pen what's the problem in it??

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How do we do the conversion

Posted by Aditya Choubey 6 years, 10 months ago

CBSE > Class 12 > Chemistry

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What is lanthenoid. Contraction

Posted by Amritpalsingh Khalsa 6 years, 10 months ago

CBSE > Class 12 > Chemistry

1 answers

Gaurav Seth 6 years, 10 months ago

A group of fourteen elements following lanthanum i.e. from ₅₈Ce to ₇₁Lu placed in 6th period of long form of periodic table is known as lanthanoids (or lanthanide series). These fourteen elements are represented by common general symbol ‘Ln’. In these elements, the last electron enters the 4f-subshells (pre pen ultimate shell). It may be noted that atoms of these elements have electronic configuration with 6s² common but with variable occupancy of 4f level. However, the electronic configuration of all the tri positive ions (the most stable oxidation state of all lanthanoids) are of the form 4f ⁿ(n = 1 to 14 with increasing atomic number). These elements constitute one of the two series of inner transition elements or f-block.
Lanthanoid contraction: In the lanthanoide series with the increase in atomic number, atomic radii and ionic radii decrease from one element to the other, but this decrease is very small. The regular small decrease in atomic radii and ionic radii of lanthanides with increasing atomic number along the series is called lanthanoid contraction.

Cause of lanthanoid contraction: When one moves from ₅₈Ce to ₇₁Lu along the lanthanide series nuclear charge goes on increasing by one unit every time. Simultaneously an electron is also added which enters to the inner f subshell. The shielding effect of f-orbitals in very poor due to their diffused shape. It results in the stronger force of nuclear attraction of the 4f electrons and the outer electrons causing decrease in size.

Consequences of lanthanoid contraction:

(i) Similarly in the properties of elements of second and third transition series e.g. Sr and Hf; Nb and Ta; Mo and W. This resemblance is due to the similarity in size due to the presence of lanthanoids in berween.

(ii) Similarity among lanthanoids: Due to the very small change in sizes, all the lanthanoids resemble one another in chemical properties.

(iii) Decrease in basicity: With the decrease in ionic radii, covalent character of their hydroxides goes on increasing from Ce(OH)₃ to Lu(OH)₃ and so base strength goes on decreasing.

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The standard reduction potential of co2+and co3+are - 0.28v and 1.8v respectively which should be a better oxidizing agent in water co2+or co3+ and why

Posted by Saroj Murra 6 years, 10 months ago

CBSE > Class 12 > Chemistry

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Copper is regarded as trasition metal though it has completely filled d-orbitals explain

Posted by Saroj Murra 6 years, 10 months ago

CBSE > Class 12 > Chemistry

1 answers

Raghav Ojha 6 years, 10 months ago

Copper forms two ions one of which has incomplete d orbitals That's why it is a transition element

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wirte a shorthand notation of cell for each of following reaction and calculate E° for each cell

Posted by Suhani Kumari 6 years, 10 months ago

CBSE > Class 12 > Chemistry

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What are legends ? And its types

Posted by Nazreen Khan 6 years, 10 months ago

CBSE > Class 12 > Chemistry

2 answers

Raghav Ojha 6 years, 10 months ago

Ligands are the molecules or atom which have atleast one lone pair and form coordination bond with central metal atom ,its types depend on its donor atom like if one then monodentate ligand

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Aruneeraj K 6 years, 10 months ago

Spell mistake

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