Question

Which polyatomic ion has a charge of 3-?(1) chromate ion (2) oxalate ion (3) phosphate ion (4) thiocyanate ion

Answer 1

(3) the Phosphate ion has a charge of 3-.

`\text{PO}_4^(-3)`

Answer 2

Answer: (3) phosphate ion

Explanation: A polyatomic ion is a ion which contains different atoms.

1) Chromate ion is a polyatomic ion containing chromium and oxygen with formula
`CrO_4^(2-)`

2) Oxalate ion is a polyatomic ion containing carbon and oxygen with formula
`C_2O_4^(2-)`

3) Phosphate ion is a polyatomic ion containing phosphorous and oxygen with formula
`PO_4^(3-)`

4) Thiocyanate ion is a polyatomic ion containing sulfur, carbon and nitrogen with formula
`SCN^(-)`