[ChargePositive]

Okay so I need to find the reactions for some chemical equations, and there are two that are giving me some trouble.

First one (For determining Ca+2 in water sample):
Na2EDTA + Ca --> (What I think the products are)CaEDTA + 2Na

And the second one(This was for a reaction in a lab for determining Oxygen in water):

Na2S2O3 + K2CrO2 --> (Can't figure these out for the life of me, can't balance)

Any help would be GREATLY appreciated, thanks!

[sjb]

Where is the Ca²⁺ in your first question?

Do you have the word equation for number two - I suspect a formula is wrong which is hindering your search.

[Vidya]

Na2S2O3 + K2CrO2 --> (Can't figure these out for the life of me, can't balance)

Any help would be GREATLY appreciated, thanks!

This equation is not correct. It should be K2Cr2O7 which reduces to Cr3+
S2O32- is oxidized to SO4 2- .It is a redox reaction and is  balanced by following some steps.
Practice redox reaction using an text book.