Use Coupon: CART20 and get 20% off on all online Study Material

Total Price: R

There are no items in this cart.
Continue Shopping
Get instant 20% OFF on Online Material.
coupon code: MOB20 | View Course list

Get extra R 650 off


how can we calculate constants 'a' & 'b' of vanderwall gas equation?


plz if by graph then provide us with the detailed procedure.



best regards


Muhib Ullah Afridi 

5 years ago


Answers : (1)


Dear student,

  • The vanderwall equation is given by


  • Here a and b are constants particular to a given gas.


  • The parameter a is related to intermolecular attractive force between the molecules , and n/V is the density of molecules

·     The term containing "a" is added to the pressure P. In other words the corrected pressure is slightly larger than the observed pressure.


·    As the  molecule moves toward the wall all of its gaseous neighbors are behind it, thus any intermolecular forces acting on the molecule are slowing it as it moves toward the wall.


·         The molecule striking the wall does so at a velocity that is slightly less (determined by the size of the intermolecular forces) than it would without these forces.

·         Or, the observed prssure is actually slightly less than the pressure would be without the intermolecular forces.

·         To correct for this, a small positive pressure must be added to the observed pressure, hence the term with "a" in it is positive.

Please feel free to ask your queries here. We are all IITians and here to help you in your IIT JEE preparation.

All the best.

Win exciting gifts by answering the questions on Discussion Forum. So help discuss any query on askiitians forum and become an Elite Expert League askiitian.

Now you score 5+15 POINTS by uploading your Pic and Downloading the Askiitians Toolbar  respectively : Click here to download the toolbar..


Askiitians Expert

Sagar Singh

B.Tech, IIT Delhi

5 years ago

Post Your Answer

Other Related Questions on Physical Chemistry

lithium tetra borate is considered as acidic flux whereas lithium meta berate is considered basic fluxwhat is the criteria for it?
In Lithium metaBorate the no. of hydrogens can be donated is superficcil than in compare to Li tetra Borate. Therfore by definition of acid – base lithium tetra borate is considered as...
2017 years ago
The molar volumes of ice and water are 0.0196 and 0.0190 litres per mole at 273K. If ΔHefor the transition of ice to water is 1440 calories per mole at 1 atm pressure, find ΔU.
Since heat is absorbed here at constant pressure so ΔH = 1440 calories ΔU can be calculated by using the formula : ΔU=ΔH-PΔV P= 1atm, ΔV = 0.0196L - 0.180L = 0.0016 L PΔV = 1*0.0016=...
navneet one month ago
Which electronic level will allow the hydrogen atom to absorb photon but not to emit ? A. 1s B. 2s C.2p D.2d
@shashank option no aturns out to be the correct option . " as its a ground state . in any energy level if electron absorba photon of energy equal to the enrgy of electron in that level...
Umakant biswal 2 months ago
D. option 2d As 2d is no orbital that is sustaining. d orbital starts with quantum number 3 check if the options are correct.
Vikas TU 2 months ago
Sir please explain what are lukars reagent and it reaction with different degree of alcohol????????
Hi ! Rama , LUCAR REAGENT (LR ) is a mixture of Zinc chloride (ZnCL 2 ) and concentrated Hydrochloric acid (Hcl).It is used to chemically distinguish different degree of alcohol. (i)When it ...
raju 2 months ago
Hi ! D.raman , It is a mixture of anhydrous ZnCl 2 and conc. Hcl. It’s reaction with different degree of alcohol -: 1 0 Alcohol-It get soluble in it. 2 0 Alcohol-Turbidity within 5 minutes. ...
nath 2 months ago
The p orbital of the charged carbon in the isopropyl cation contains how many electrons?
On writing the configuration of the charged carbon in that isopropyl cation U would get the configuration of Carbon and U would find that there are 4 electrons in the last p orbital of...
Vikas TU 28 days ago
While drawing a structure of a compound how do we decide that where to place the Lone pair
@ rahul u can place that anywhere , no doub t for symmatry , just u need to be clear with the meaning of the loan pair , that means theses are the electron pairs which cannot participate in ...
Umakant biswal 9 days ago
The l.p. should arrange in this way thatl.p.----l.p. don`t allow on 90° and l.p-----b.p.(bond pair) is≥ 120° .And keep in mind less repultion between l.p.and b.p.
3 days ago
View all Questions »

  • Complete JEE Main/Advanced Course and Test Series
  • OFFERED PRICE: R 15,000
  • View Details
Get extra R 3,750 off

Get extra R 650 off

More Questions On Physical Chemistry

Ask Experts

Have any Question? Ask Experts

Post Question

Answer ‘n’ Earn
Attractive Gift
To Win!!!
Click Here for details