help with chemistry question? :( (2 Viewers)

[s0phie92]

1.380g of an iron salt was dissolved in 25.00mL of distilled water. The solution was titrated against 0.100M Na2Cr2O7
and the titr
e was 12.78mL
Using the half - reaction below,
Cr2O7(-2) + 14H(+) + 6e(-) ---> 2Cr(3+) + 7H2O
what was the formula of the iron salt?

the answer is iron nitrate

please help i dont understand how to get the answer
thanks!