tetraphosphorus, commonly known as white phosphorus, forms different compounds with chlorine depending on the amount of chlorine present. If chlorine is limited, phosphorus trichloride is formed. If there is an excess of chlorine, phosphorus pentachloride is formed. Write balanced equations for the two reactions of white phosphorus with chlorine.

Question

somy · Answer

how about trying yourself first?

anonymous · Answer

I got 2P4 + 2Cl2 -> 4PCl + P4 for the first equation

somy · Answer

read the question once again

anonymous · Answer

wouldn't there be excess phosphorus if chlorine is limiting?

somy · Answer

There are 2 types of products possible when P reacts with Cl

anonymous · Answer

oh oops its PCl3

somy · Answer

$PCl_3$ 
or 
$PCl_5$

anonymous · Answer

1 second I'll re-balance

somy · Answer

$PCl_3$ - when chlorine is limiting 
$PCl_5$ - when chlorine is in excess

anonymous · Answer

ok so 2P4 + 6Cl2 -> 4PCl3 + P4

somy · Answer

2P4 + 6Cl2 -> 4PCl3 + P4

why do u have P4 in product side?

somy · Answer

in each case only 1 product is formed!

anonymous · Answer

because there's excess tetraphosphorus isn't there?

anonymous · Answer

@Somy

somy · Answer

No

somy · Answer

Its excess CHLORINE

somy · Answer

NOT phosphorus

anonymous · Answer

why though because chlorine is limiting

somy · Answer

look when P and Cl react 
this is ADDITION reaction

somy · Answer

when chlorine is in limited amount - the product formed will be PCl3 
but when there is enough chlorine -the product formed will be PCl5

anonymous · Answer

so there's nothing else besides that on the product side?

somy · Answer

5 bonds- is maximum number of bond P can make 
so in case if Cl is less - it'll make 3 bonds with Cl 
if Cl is more then its enough to use all 5 last shell electrons for bonding with Cl

somy · Answer

yes.

anonymous · Answer

so it's:
P4 + 6Cl2 -> 4Pcl3
P4 + 10Cl2 -> 4PCl5

somy · Answer

yup

anonymous · Answer

Thank you! How would I design an experiment to verify this?

anonymous · Answer

i would take molCl<molP4 and then combine right?

somy · Answer

hmm i don't really know about experiment part  
but well in one case u'll take limited amount of Cl while in other case you'll take excess amount of Cl

anonymous · Answer

thanks :)

somy · Answer

no problem :)