Adsorption is the presence of excess concentration of any particular component at the surface of liquid a solid phase as compared to bulk.This is due to presence of residual forces at the surface of body.In the adsorption of hydrogen gas over a sample of charcoal, `1.12cm^3` of `H_2(g)` measured over S.T.P was found to absorb per gram of charcoal.Consider only monolayer adsorption.Density of `H_2` is 0.07gm/cc. In another experiment same 1 gm charcoal adsorbs 100 ml of 0.5M `CH_3COOH` to form monolayer and thereby the molarity of `CH_3COOH` reduces to 0.49.
`((3xx47.43)/(4pi))^(1//3)=2.24`
`(2.24)^2=5`
Surface area of charcoal adsorbed by each molecule of (acetic soda) is-

Options

A. `7.8xx10^(-19) cm^2`
B. `7.8xx10^(-18) cm^2`
C. `7.8xx10^(-17) cm^2`
D. `7.8xx10^(-16) cm^2`

Answer

C

Explanation

moles of acetic acid used `=0.5xx100/1000-0.49xx100/1000=10^(-3)`moles
number of molecules `=10^(-3)xx6.023xx10^23=6.023xx10^20`
surface area of charcoal `=4.73xx10^4 cm^2`
surface area of charchol adsorbed by each molecule`=(4.73xx10^4)/(6.023xx10^20)=7.8xx10^(-17) cm^2`