Question

QUESTION 35 Diffusion is defined as the spontaneous mixing of gas samples. Ammonia and HCl solutions both give off the dissolved gases if exposed to air and will diffuse through the air. Ammonia and HCl on contact react to form a white solid. A cotton ball soaked with ammonia was placed at one open end of a hollow tube and a cotton ball soaked with HCl was placed at the other open end of a hollow tube. The gases began to diffuse through the air in the tube toward each other. If the ammonia molecules are smaller in mass than the HCl molecules, which of the following statements would be correct? Closer to NH; Exactly half-way closer to HCI NH,soaked cotton ball at this end HCl soaked cotton ball at this end The white solid would form exactly half-way between the two ends of the tube. The white solid would form closer to the end of the tube where the ammonia-soaked cotton ball was placed. The white solid would form closer to the end of the tube where the HCl-soaked cotton ball was placed.

Answer 1

Question 35- Acconding to Gnahams laus of dfusion a gas the is invensely phoportional to Square noot its molecular mass the nali of diftusion of Afusion of Yate Jas Holecula mass4gas) a (a) YMI constant M M2 M / let Y, is rati d dituon ogas be Yale of diffusion gas 2

Let the rate of diffusion of NH3 be R1

Molecular mass of ammonia = 17g/mol

Let the rate of diffusion of HCl be R2.

Molecular mass of HCl = 36.5g/mol

Substitute this values in equation (1)

We get R1 /R2 = $\sqrt{}$ (36.5 g /mol )/ (17 g/mol)

=> R1 /R2 = 1.46

=> R1 = 1.46R2

Hence, ammonia diffuses fasley tham Hcl NH.C + HC 3 (3) 4 ( 9) NH3 > NH C(S) As ammonia diffuses faster tham Hc NC () tms nearer to HC Hence the Xast option, i.e the white solid end of the tube where the Hc fim closer to the coton ball was placed Spaked