Hydrolysis of a compound B(C7H6CL2) was carried out by refusing with excess potassium hydroxide solution.The resulting solution was acidified with dilute nitric acid and excess silver nitrate added to precipitate the chloride ions as Silver Chloride, 0.718g was found from 0.805g of B

a. Calculate the number of chlorine atoms present in each molecule of B which are liberated by hydrolysis.
b. Suggest an explanation for result obtain in a.
c. Give a possible structure of B.

Be notified that I am not an organic chemist (I AM a chemist though) and here is what I think.

mols AgCl = grams/molar mass = 0.718/143.3 = 0.005
mols B = 0.805/161 = 0.005
a. According to the data above, there is 1 Cl atom in each molecule of B.
b. We might expect 2, of course, from the formula; howeverr, what we have is a molecule that has the Cl atoms attached in different ways. One can be pulled off easily and the other stays attached. So the AgNO3 shows just one because only one atom Cl per molecule B was hydrolyzed.
c. The best choice I can come up with, and I've spent more than three hours trying this and trying that (an organic chemistry would have known enough s/he would have known exactly what to do) is 4-chlorobenzyl chloride. The Cl on the CH2Cl part of B is the one we find in hydrolysis. The Cl attached to the 4 position of the benzene ring does not give the Cl/AgNO3 test.
Hope this helps.

The answers are correct, but I don't really comprehend the answer for c

To answer the given questions, we need to understand the chemical reactions involved and use stoichiometry.

a. To calculate the number of chlorine atoms present in each molecule of B liberated by hydrolysis, we need to determine the molar mass of B(C7H6Cl2).

The molar mass of B(C7H6Cl2) can be calculated as follows:
(7 * 12.01 g/mol) + (6 * 1.01 g/mol) + (2 * 35.45 g/mol) = 197.16 g/mol

Now, we can use stoichiometry to determine the number of moles of B:

0.805 g B * (1 mol B / 197.16 g B) ≈ 0.00409 mol B

Since the balanced chemical equation for the hydrolysis of B shows 1 mole of B liberating 2 moles of chloride ions (Cl-), we can calculate the number of moles of chloride ions using the stoichiometric ratio:

0.00409 mol B * (2 mol Cl- / 1 mol B) ≈ 0.00818 mol Cl-

Finally, we can determine the number of chlorine atoms present in each molecule of B:

0.00818 mol Cl- * (6.02 x 10^23 atoms/mol) ≈ 4.92 x 10^22 chlorine atoms

Therefore, there are approximately 4.92 x 10^22 chlorine atoms present in each molecule of B.

b. The result obtained in part a suggests that there are two chloride ions (Cl-) liberated from each molecule of B by hydrolysis. This indicates that the molecule B contains two chlorine atoms. The presence of two chlorine atoms is confirmed by the formation of 0.718 g of silver chloride (AgCl), as stated in the problem.

c. To suggest a possible structure of B, we need more information. The given chemical formula, B(C7H6Cl2), does not provide enough details to accurately determine the structure of B. However, based on the presence of two chlorine atoms and the molecular weight of B, it suggests the possibility of a symmetrical organic compound with two chloro-substituted phenyl (C6H5) groups attached to a central carbon or another atom. The specific structure would require more information or experimental data to accurately determine.