Question

In what proportions do Cr3+ andO2- to produce a neutral compound

Answer 1

So we know that chromium has a 3+ charge on it (
`Cr^(3+)`) and oxygen has a 2- charge (
`O^(2-)`.

In order to create a neutral compound, the charges on these atoms must cancel each other out. The best way to do this quickly is to take the charge of the other atom and make it the subscript for the atom of interest.

For example, lets look at chromium. The oxygen has a charge of 2-, so we're going to make the amount of chromium in the new compound with a subscript two: (
`Cr_(2)`)

Now look at oxygen. The chromium has a charge of 3+, so we're going to make the amount of oxygen in the new compound with a subscript three: (
`O_(3)`)

Then we put them together to make the new neutral compound:
`Cr_(2)O_(3)`

So when we look at this ratio, we see that Cr:O must be 2:3 in order to remain a neutral compound.

Answer 2

The proportions of chromium (III) ion and oxide ion to produce a neutral compound is 2: 3.

This results in the formation of a neutral compound
`Cr_2O_3`

Step-by-step explanation:

Valency of chromium ion = 3+

Valency on oxygen ion = 2-

By criss-cross method, the oxidation state of the ions gets exchanged and they form the subscripts of the other ions.

This results in the formation of a neutral compound:

`2Cr^(3+)+3O^(2-)\rightarrow Cr_2O_3`

This results in the formation of a neutral compound
`Cr_2O_3`

The proportions of chromium (III) ion and oxide ion to produce a neutral compound is 2: 3.