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

In thermodynamics, the Gibbs free energy is a thermodynamic potential that can be used to calculate the maximum of reversible work that may be performed by a thermodynamic system at a constant temperature and pressure

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What is the mass of urea( molar mass60g/mol)dissolved in 50g of water so as the vapour pressure of the solution reduced to 25%.

Posted by Aarav Gahlawat 7 years, 4 months ago

CBSE > Class 12 > Chemistry

2 answers

Aarav Gahlawat 7 years, 4 months ago

If we not neglect the moles of solvent in denominator; can we still get the right answer

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Prerna Kumari 7 years, 4 months ago

Let VP of water be 100 then VP of solution is 25 Therefore, (100-25)/100 = mole of urea÷ mole of water, 75/100 = (m/60) ÷ (50 /18), 75/100 = 3 m / 500, m = (75×5)/3= 125gm. Hence mass of urea = 125gm

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Ph3 has lowering boiling point than nh3 why?

Posted by Pooja Nandu 7 years, 4 months ago

CBSE > Class 12 > Chemistry

1 answers

Anushka Priya 7 years, 4 months ago

Because nh3 is smaller in size N2 Forms multiple bonds , Absence of d orbital . Hence ph3 breaks easily as it have single bond , Longer bond length , so it breaks easily

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What is vapour pressure??exact definition.....

Posted by Rutu Gond 7 years, 4 months ago

CBSE > Class 12 > Chemistry

1 answers

Möñäłïšä Àđhíkàŕÿ 7 years, 4 months ago

" VAPOUR PRESSURE of a liquid/solution is the pressure exerted by the vapours in equilibrium with the liquid/solution at a particular temperature ". Factors affecting vapour pressure are : (a) Nature of the liquid , and (b) Temperature.

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Helium is used in diving appratus. Give reason

Posted by Dharmendra Singh 7 years, 4 months ago

CBSE > Class 12 > Chemistry

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Order of Electronegativity of group 15?

Posted by Nitish Sharma 7 years, 4 months ago

CBSE > Class 12 > Chemistry

1 answers

Shubham Thakur 7 years, 4 months ago

Order of the electronegativity goes down the group is decreasing

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Emulsification

Posted by Abhishek Yadav 7 years, 4 months ago

CBSE > Class 12 > Chemistry

2 answers

Bhumika Rana 7 years, 4 months ago

It is the preparation of a colloidal sol in which the dispersed phase and dispersed medium both are liquids.

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Prerna Kumari 7 years, 4 months ago

The process through which emulsion( a colloidal sol in which both the dispersion phase and despersion medium is liquid) will form is known as emulsification

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200mlof 1M HCl is mixed with 300ml of 6M HCl and the final solution is diluted to 1000 ml. Calculate molar concentration of [H+] ion.

Posted by Neha Singh 7 years, 4 months ago

CBSE > Class 12 > Chemistry

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Butter is an example of which type of colloid? Explain.

Posted by Prerna Kumari 7 years, 4 months ago

CBSE > Class 12 > Chemistry

1 answers

Neha Singh 7 years, 4 months ago

It is emulsion type of colloid

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Explain following reaction with an example??? 1. Stephen reaction 2.Etard reaction

Posted by Yogesh Yadav 7 years, 4 months ago

CBSE > Class 12 > Chemistry

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lyophilic lyophilic

Posted by Vivek Singh 7 years, 4 months ago

CBSE > Class 12 > Chemistry

2 answers

Abhay Srivastav 7 years, 4 months ago

Liquid loving is lyophilic & liquid hating is lyophobic

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Rishabh Sahu 7 years, 4 months ago

Lyophillic - SOLVENT LOVING Lyophobic - SOLVENT HATING

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By use one mole of compound in a chemical reaction it is observed that reaction take 1 hour for its 3 upon 4 decompose Calculate rate constant K for the reaction if follow first order reaction

Posted by Pallavi Rani 5 years, 8 months ago

CBSE > Class 12 > Chemistry

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what is nernst equation

Posted by Abhishek Yadav 7 years, 4 months ago

CBSE > Class 12 > Chemistry

3 answers

Abhay Srivastav 7 years, 4 months ago

It is necessary to introduce nerst equation because the concentration of all the species involved in the electrode reaction is not need to be unity (Cell potential = standard cell potential - RT/nF log[product concentration] /[reactant concentration]

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Arihant Yadav 7 years, 4 months ago

Nernst equation is an equation which help us to determine emf of a cell ...it is given be Emf (cell)=cell potential -0.0591/n ×log[product]/[reactant ]. Where n is no.of electrons taking palce in reaction or no.of electrons canclled diring finalisation of equation.

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Vivek Singh 7 years, 4 months ago

-nef

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Why half filled electrons are more stable than full filled electrons?

Posted by Abhishek Shukla 7 years, 4 months ago

CBSE > Class 12 > Chemistry

2 answers

Abhay Srivastav 7 years, 4 months ago

They have less energy as compare to full filled e -

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Shubham Thakur 7 years, 4 months ago

Due to symmetry

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Explain zone refining

Posted by Abhinav Ahlawat 7 years, 5 months ago

CBSE > Class 12 > Chemistry

1 answers

Yogita Ingle 7 years, 5 months ago

Zone refining: This method is based on the principle that impurities are more soluble in the molten state of metal (the melt) than in the solid state. In the process of zone refining, a circular mobile heater is fixed at one end of a rod of impure metal. As the heater moves, the molten zone of the rod also moves with it. As a result, pure metal crystallizes out of the melt and the impurities pass onto the adjacent molten zone. This process is repeated several times, which leads to the segregation of impurities at one end of the rod. Then, the end with the impurities is cut off. Silicon, boron, gallium, indium etc. can be purified by this process.

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Question related to Density

Posted by Simran Kamboj 7 years, 5 months ago

CBSE > Class 12 > Chemistry

1 answers

Nitish Sharma 7 years, 4 months ago

What type of Questions r u looking for simran?

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CH3-co-ch-ch2

Posted by Abhishek Yadav 7 years, 5 months ago

CBSE > Class 12 > Chemistry

2 answers

Abhay Srivastav 7 years, 4 months ago

Butan2one

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Hasan Ali 7 years, 5 months ago

But-2-one

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Write the type of adsorption

Posted by Mahi Kumar 7 years, 5 months ago

CBSE > Class 12 > Chemistry

3 answers

Harshit Thakur 7 years, 5 months ago

Physisorption and chemisorption

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Nitish Sharma 7 years, 5 months ago

Physical adsorption and chemical adsorption

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Sweety Sweety 7 years, 5 months ago

Positive and negative adsorption

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Is modern abc of chemistry included all ncert examples and exercises

Posted by Abhat Singh 7 years, 5 months ago

CBSE > Class 12 > Chemistry

2 answers

Aj Style 7 years, 4 months ago

May be!

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Hasan Ali 7 years, 4 months ago

No it contain few of them

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H2 is heated with 100 Celsius what happened

Posted by Dablu Rj 7 years, 5 months ago

CBSE > Class 12 > Chemistry

1 answers

Hasan Ali 7 years, 4 months ago

When h2 is heated with 100 celcius It reacts with atmospheric o2 and give the water and h2o2

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Why H2S a neutral and H2S is acidic

Posted by Shubham Thakur 7 years, 5 months ago

CBSE > Class 12 > Chemistry

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Why NH3 is high melting and boiling point as compared to other hydrides of the same group

Posted by Shubham Thakur 7 years, 5 months ago

CBSE > Class 12 > Chemistry

1 answers

Pranav Sharma 7 years, 5 months ago

Because NH3 makes hydrogen bond where as other elements of same group do not form hydrogen bond in their hydrides

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Why NH3 is liquid and PH3 is gas

Posted by Shubham Thakur 7 years, 5 months ago

CBSE > Class 12 > Chemistry

1 answers

Tushar Jaryal 7 years, 5 months ago

Due to hydrogen bonding only...which is a stronger interaction then diple diple interaction present in PH3

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What is the effect of temperature in molality

Posted by Yo Yo Honey Singh ? 7 years, 5 months ago

CBSE > Class 12 > Chemistry

1 answers

Anjana Sherawat 7 years, 5 months ago

No effect

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What are ambient nucleophile ?give example

Posted by Yo Yo Honey Singh ? 7 years, 5 months ago

CBSE > Class 12 > Chemistry

4 answers

We Ayush 7 years, 4 months ago

The nuceophile have more than one electron rich centre.formation of product which will attack is decided btly hard soft acid base theory hard mrans high electron density .ths theory tells that hard plus hard stable this why RBr plus nacn is alkyl cyanide whereas Rbr plus agcn is alkyl isocyanide

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Anjana Sherawat 7 years, 5 months ago

More than one site

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Anjana Sherawat 7 years, 5 months ago

Nucleophile which have more than one through with reaction can occur Ex- -CN,-NO2

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Pooja Sharma 7 years, 5 months ago

These are those nucleophiles which has two nucleophilic centers . Ex is CN

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Give an example of a solid solution in which the solute is a gas

Posted by Yo Yo Honey Singh ? 7 years, 5 months ago

CBSE > Class 12 > Chemistry

1 answers

Sweety Sweety 7 years, 5 months ago

A rusting iron .. On it co2 gas is there

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About adsorption

Posted by Sahil Akhtar 7 years, 5 months ago

CBSE > Class 12 > Chemistry

5 answers

Abhinav Sharma 7 years, 5 months ago

it is chalk

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Subhash Chand 7 years, 5 months ago

Particles are accumulate only at the surface of any substance. ex.-- When we dip a chack into ink we see the chack blue from outside but when we break the chack we see the chack white from inside. Because the particles of ink accumulate only at the surface of chack not in the bulk

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Subhash Chand 7 years, 5 months ago

Particles accumulate only at the Surface

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Simran Miyan 7 years, 5 months ago

The accomodation of adsorbate on the surface of adsorbent where adsorbate is like solute and adsorbent is like solvent . It is a sruface phenomena

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Mohit Sepat 7 years, 5 months ago

Absorption from surface

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The ratio of Fe valenci 3+and Fe2+ions in Fe0.9 S1.0 is