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

Elctrons does not fall on nucleous because electrons are bounded in 0rbit by limited nucleus attraction force and also attracted by multiple forces on it.

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1.0g of a non volatile solute was dissolved in 100g of acetone at 298 K. The vapour pressure of solution was found to be 192.5 mm of Hg. Calculate molar mass of solut.

Posted by Swati Yadav 6 years, 6 months ago

CBSE > Class 12 > Chemistry

1 answers

Manasvi Mahajan 4 years, 7 months ago

44.16

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Notes of ch 14

Posted by Abhay Chauhan 6 years, 6 months ago

CBSE > Class 12 > Chemistry

4 answers

Srishti Choudhary ✍⏳ 6 years, 6 months ago

See in the app

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Abhay Chauhan 6 years, 6 months ago

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Kajal Kunwar 6 years, 6 months ago

Learncbse .com is best

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Anubhuti Khatri 6 years, 6 months ago

Check cbse revision notes

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Why asprene is used by heart person

Posted by Aditya Rathore 6 years, 6 months ago

CBSE > Class 12 > Chemistry

5 answers

Kajal Kunwar 6 years, 6 months ago

What is aspirin?

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Ďãřşháñăã Yadav???✊ 6 years, 6 months ago

Aspirin is used in this situation becoz during heart attack our blood develop a clot which obstruct the flow of oxygen and blood to the heart. Aspirin interferes the cloting of blood in this situation and make it thin so that it can easily flow and supply required amount of Oxygen to the heart.

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Sayeda Iram Ateeq 6 years, 6 months ago

Aspirin is effective in reducing the blood clots that are blocking a coronary artery during an acute heart attack. That's why it is used by the people who have already had a heart attack or who have an increased risk of having one in the future.

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Aditya Rathore 6 years, 6 months ago

How

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Sayeda Iram Ateeq 6 years, 6 months ago

Because it works as clot buster!

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Define the zero order .

Posted by Jasmine Jasmine 6 years, 6 months ago

CBSE > Class 12 > Chemistry

3 answers

Aditya Rathore 6 years, 6 months ago

I have an example also if you want

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Aditya Rathore 6 years, 6 months ago

When rate of rxn is directly perportional to zero power of consentration of reactant molecule this type of rxn called zero order rxn

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Sia ? 6 years, 6 months ago

A chemical reaction in which the rate of reaction is constant and independent of the concentration of the reacting substances.

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How can I get 90 above in my board exam 2020 ?Please give me some tips .

Posted by Prabhat Emmanuel 6 years, 6 months ago

CBSE > Class 12 > Chemistry

3 answers

Srishti Choudhary ✍⏳ 6 years, 6 months ago

Focused only on study not on social media?

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Swati Singh 6 years, 6 months ago

Jst work hard!

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Aditya Rathore 6 years, 6 months ago

From study

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How we extract metal from ore

Posted by Himanshu Chaturvedi 6 years, 6 months ago

CBSE > Class 12 > Chemistry

1 answers

Yogita Ingle 6 years, 6 months ago

The process of extracting metal ores buried deep underground is called Mining. The metal ores are found in the earth’s crust in varying abundance. The extraction of metals from ores is what allows us to use the minerals in the ground! The ores are very different from the finished metals that we see in buildings and bridges. Ores consist of the desired metal compound and the impurities and earthly substances called Gangue. The extraction of metals and its isolation occurs over a few major steps:

Concentration of Ore
Isolation of metal from concentrated Ore
Purification of the metal

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Hypertonic

Posted by Arvind Meena_Official 6 years, 6 months ago

CBSE > Class 12 > Chemistry

0 answers

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Solid states ana hai 12 board exams ma

Posted by Manu Thakur 6 years, 6 months ago

CBSE > Class 12 > Chemistry

5 answers

Sajid Ali 6 years, 6 months ago

It will not come in board exam but come in entrance exam

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Akanksha Kumari? 6 years, 6 months ago

Ya it's not coming in boards

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Chandrashekhar Shekhar 6 years, 6 months ago

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Manika Gupta 6 years, 6 months ago

No..it is deleted

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꧁≪Mämƭå ℭℏ۝ᑌĎℎàℜÿ? 6 years, 6 months ago

No, it is deleted from 2019-20 syllabus...it will not come in board exams

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Why Adsorption always exothermics????

Posted by Aman Kumar 6 years, 6 months ago

CBSE > Class 12 > Chemistry

5 answers

Niharika Sihag 6 years, 6 months ago

During adsorption there is decrease in surface energy so heat is released that's why it is exothermic

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Aman Kumar 6 years, 6 months ago

Dhanyawad apka??

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Ďãřşháñăã Yadav???✊ 6 years, 6 months ago

by chance send incomplete answer .second one is correct one. ?

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Ďãřşháñăã Yadav???✊ 6 years, 6 months ago

during adsorption there is always a decrease in residual or unbalanced forces of the surface. this results in decrease in surface energy which appears as heat, therefore adsorption is an exothermic process.

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Ďãřşháñăã Yadav???✊ 6 years, 6 months ago

during adsorption there is always a decrease in residual or unbalanced forces of

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H20 is liquid while H^2s is gad

Posted by Prince Rabbani 6 years, 6 months ago

CBSE > Class 12 > Chemistry

1 answers

꧁≪Mämƭå ℭℏ۝ᑌĎℎàℜÿ? 6 years, 6 months ago

In H2O , oxygen is highly electonegative and attracts the hydrogen and form a strong bond called hydrogen bond due to strong bond the intermolecular forces of attraction is more and they come closer and the distance between the bonds decreases, this results in formation of liquid whereas in case of H2S sulphur is less electronegative and dont have tendency to form hydrogen bond, it forms weak bonds held by weak vander waal's forces....thus the atoms are far from each other and this leads to gas.

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Calculate Molar conductivity 1.028×10^-3M. Acetic acid having conductivity 4.95×10^-5 siemens/cm

Posted by Suraj Raj Shrivastava 6 years, 6 months ago

CBSE > Class 12 > Chemistry

1 answers

Ďãřşháñăã Yadav???✊ 6 years, 6 months ago

OK see what we have given in the question ✴️concentration M = 1.028*10^-3 nd conductivity k = 4.95*18^-5 now we have the formula for finding Molar conductivity Λ. which is Λ= κ*1000/Μ now put the values in it . Λ= 4.95*10^-5 ×1000/ 1.028 *10^-3 solve this u will get the answer 48. 15 s cm²/mol.

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Find the molar conductivity of 0.1 mol/litre kcl solution having conductivity 1.29 siemens/m.

Posted by Suraj Raj Shrivastava 6 years, 6 months ago

CBSE > Class 12 > Chemistry

1 answers

Akshat Singh 6 years, 6 months ago

Molar conductivity =conductivity ×1000/Molarity =1.29 ×1000 /0.1 =12900 Sm^2/mol

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Has anyone completed english core til now?

Posted by ꧁≪Mämƭå ℭℏ۝ᑌĎℎàℜÿ? 6 years, 6 months ago

CBSE > Class 12 > Chemistry

8 answers

Kajal Kunwar 6 years, 6 months ago

Oh god..

1Thank You

Aman Kumar 6 years, 6 months ago

I had not taken bio....I'm a CS Student

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꧁≪Mämƭå ℭℏ۝ᑌĎℎàℜÿ? 6 years, 6 months ago

Ok...in biology

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Aman Kumar 6 years, 6 months ago

From Flamingo...6 to 7 chapters ... And rest of them has also to be revise , bahot pehle padha tha unn chapters ko?

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꧁≪Mämƭå ℭℏ۝ᑌĎℎàℜÿ? 6 years, 6 months ago

How many chapters are left to be completed?

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Aman Kumar 6 years, 6 months ago

Not completed whole english core...some chapters are left

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Ďãřşháñăã Yadav???✊ 6 years, 6 months ago

nope. ?

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Sanjay Kumar Sanjay Kumar 6 years, 6 months ago

Chemistry objecaty

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Describe the preparation of colloidal solution of ferric chloride ?

Posted by Anubhuti Khatri 6 years, 6 months ago

CBSE > Class 12 > Chemistry

0 answers

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Calculate the molarity of water if its density is 1000kg/m^3

Posted by Shraddha Vala 6 years, 6 months ago

CBSE > Class 12 > Chemistry

1 answers

Sia ? 6 years, 6 months ago

1 liter of water =1 kg
or 1000 ml water =1 kg [Given d = 1000 kg/m³]
Moles of water present in 1000 ml = {tex}\frac{1000}{18}{/tex}= 55.55
Hence molarity of water is 55.55 M

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Please send Chemistry prectical With link.

Posted by Shiv Kumar 6 years, 6 months ago

CBSE > Class 12 > Chemistry

0 answers

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Henry law constant for co2 dissolving in water is 1.67into10_8 pa when packed under 2.5 atm. Co2 pressure at 298 K

Posted by Malik Shab 6 years, 6 months ago

CBSE > Class 12 > Chemistry

1 answers

Sia ? 6 years, 6 months ago

It is given that:
KH = {tex}1.67\times10^8Pa{/tex}
{tex}{P_{c{o_2}}}{/tex} = 2.5 atm = {tex}2.5\times1.01325\times10^5Pa{/tex}
{tex}=2.533125\times10^5Pa{/tex}
According to Henry's law:
{tex}P_{CO_2}=K_{H\;}\;x{/tex}
{tex}x = \frac{{Pc{o_2}}}{{{K_H}}}{/tex}
{tex}\frac{{2.533125 \times {{10}^5}}}{{1.67 \times {{10}^8}}}{/tex}
= 0.00152
We can write, {tex}x = \frac{{{n_{co}}_{_2}}}{{{n_{c{o_2}}} + {n_{{H_2}O}}}} \approx \frac{{{n_{c{o_2}}}}}{{{n_{{H_2}O}}}}{/tex}
[Since, {tex}{n_{c{o_2}}}{/tex}is negligible as compared to {tex}{n_{{H_2}O}}{/tex}]
In 500 mL of soda water, the volume of water = 500 mL
[Neglecting the amount of soda present]
We can write:
500 mL of water = 500 g of water
={tex}\frac{{500}}{{18}}{/tex} mol of water
= 27.78 mol of water
Now, {tex}\frac{{{n_{c{o_2}}}}}{{{n_{{H_2}O}}}} = x{/tex}
{tex}\frac{{{n_{c{o_2}}}}}{{27.78}} = 0.00152{/tex}
{tex}{n_{c{o_2}}} = 0.042\,mol{/tex}
Hence, quantity of CO₂ in 500 mL of soda water = {tex}(0.042 \times 44)g{/tex}
= 1.848 g

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Give an example of solution in which both a solute and solvent are solid

Posted by Chinthem Sitlhou 6 years, 6 months ago

CBSE > Class 12 > Chemistry

4 answers

Aman Kumar 6 years, 6 months ago

Alloys ....It is the combination of two or more metals where solute and solvent both are solid

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꧁≪Mämƭå ℭℏ۝ᑌĎℎàℜÿ? 6 years, 6 months ago

Maybe alloys

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Sia ? 6 years, 6 months ago

Bronze is a solid solution. Tin is the solute and copper is the solvent.

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Jahnvi Singh 6 years, 6 months ago

One example is gold dissolved in copper

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Show that depression of freezing point is a colligative property.

Posted by Roshan Kumar Thakur 6 years, 6 months ago

CBSE > Class 12 > Chemistry

1 answers

Akshat Singh 6 years, 6 months ago

Yes, it is a colligative property because it depends on number of solute particles.

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Show that elevation of boiling point is a colligative property.

Posted by Roshan Kumar Thakur 6 years, 6 months ago

CBSE > Class 12 > Chemistry

2 answers

Harmandeep Singh 6 years, 6 months ago

It is Xb=P°a-Pt÷P°a where Xb is mole fraction of solute. And mole fraction of solute needs no.of solute particles so it is colligative property

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Akshat Singh 6 years, 6 months ago

Yes, it is a colligative property because it depends on number of solute particles( Wb, Mb).

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Which chapter is deducted in chemistry class 12 for board exam 2019-20

Posted by Rahul Yadav 6 years, 6 months ago

CBSE > Class 12 > Chemistry

3 answers

Akanksha Kumari? 6 years, 6 months ago

Solid state is deleted

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Aman Kumar 6 years, 6 months ago

Its 1st chapter ..Solid state....but in some school it still being taught

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∂Αяѕнαиαα ყα∂Αѵ ??? 6 years, 6 months ago

solid state .

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What is NBS

Posted by Nasima Khan 6 years, 6 months ago

CBSE > Class 12 > Chemistry

2 answers

Sia ? 6 years, 6 months ago

N-Bromosuccinimide or NBS is a chemical reagent used in radical substitution, electrophilic addition, and electrophilic substitution reactions in organic chemistry.

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Nasima Khan 6 years, 6 months ago

A lot of thank u sia

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When chlorine is passed through warm benzene in presence of the sunlight the product is

Posted by Nasima Khan 6 years, 6 months ago

CBSE > Class 12 > Chemistry