Chemistry - Surface Chemistry Question with Solution | TestHub

ChemistrySurface ChemistryAdsortionMedium2 minQB

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Passage / Comprehension

1 gram of activated charcoal has a surface area of $1 0^{3} m^{2}$ . Complete coverage of the charcoal surface by NH₃ molecules is assumed by monolayer formation. The diameter of each NH₃ molecule is 4 Å. Ammonia is adsorbed on the charcoal by two-dimensional close-packed arrangements with maximum efficiency.

In another experiment, $103 g m$ of the given charcoal is treated with 100 mL of 5 M ammonia solution. After adsorption, the excess ammonia solution is removed. Given: $N_{A} = 6 \times 1 0^{23}$ .

As per the second experiment what is the molarity of excess ammonia solution removed (nearly) ?

Options:

Answer:

Solution:

Number of NH₃ molecules adsorb will be

$\frac{10 3 \times 1 0 ^{3}}{8 3 \times 1 0 ^{- 20}} = 1.25 \times 1 0^{23}$

moles of NH₃ =Adsorb= $\frac{1.25 \times 1 0 ^{23}}{N _{A}} \approx 0.2$ mol.

Remaining moles = $0.5 - 0.2 = 0.3$

So, the final molarity = $\frac{0.3}{100/1000} = 3$ M.

Stream:JEESubject:ChemistryTopic:Surface ChemistrySubtopic:Adsortion

⏱ 2mℹ️ Source: QB

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