Suggest with reasons, to which group of the Periodic Table element X b

[Kushal]

Homework Statement

Element X forms a chloride, XCl_n which melts at 3$$\circ$$C. When 0.500 g of the chloride reacts with an excess of acidified silver nitrate, 1.19g of AgCl are formed.

Another 0.500g sample of the chloride is heated strongly and chlorine gas is given off. When the residue is treated with an excess of acidified silver nitrate, only 0.714g of AgCl is precipitated.

(1) Predict the type of bonding in XCl_n.
(2) Suggest with reasons, to which group of the Periodic Table element X belongs.
(3) Calculate the value of n and attempt to identify X.

Homework Equations

The Attempt at a Solution

(1) It is covalent because of the low melting point.

(2) I would say group 5 or 6 because the chlorides exhibits several valencies. (but i don't know which one to choose) and the question asks for reasonS<---

(3) I am completely lost and confused. I calculated the number of mol of AgCl formed in both cases knowing that the difference between these values should give me something important. but i don't know what.


and i think X is phosphorous because PCl₅ decomposes into PCl₃ on heating. but the question does not ask for this kind of reasoning.

 

[Borek]

If it is XCl₃, and if 0.500 g contains the same amount of chlorine as 1.19 g of AgCl, what is molar mass of X?

 

[chemisttree]

...and i think X is phosphorous because PCl₅ decomposes into PCl₃ on heating. but the question does not ask for this kind of reasoning.

MP (with sublimation) for PCl₅ is 100^oC.


Use the total #moles of Cl to determine the atomic weight of X possible for n=1,2,3,4,5,6,7,8.
You will note that n=1 is unlikely since upon heating, some Cl remains behind. Two Cl-'s have changed from chloride to Cl^o (an oxidation) The X must have been reduced by an equal amount.

After heating you have some Cl left. Use the total #moles of Cl that remain after heating to determine the atomic weight of X possible for the new "n"=1,2,3,4,5,6,7,8,...

Any overlap?

 

[Borek]

Sorry, no idea where have I read this 3 in XCl_n

But the idea remains the same, just - as chemisttree wrote - calculate molar masses for different values of n.

 

[Kushal]

it is not phosphorous then...

i understood what you meant, i already found the possible A_r of X for XCl_n.

but i need the mass of the residue after heating (it is no longer 0.5g because some Cl has been liberated from it). how can i find that?

does (1.19 - 0.714) give you the mass of chlorine liberated?

thnks

 

[Borek]

does (1.19 - 0.714) give you the mass of chlorine liberated?

Indirectly. These are masses of AgCl. But you are on the right track.