A `0.002 M` aqueous solution of an ionic compound `[Co(NH_(3))_(5)(NO_(2))] Cl` freezes at `-0.00732^(@)C`. Find the number of moles of ions which `1` mole of ionic compound produces of being dissolved in water. `(K_(f) = -1.86^(@)C//m)`.

Options

A. `3`
B. `4`
C. `1`
D. `2`

Answer

4

Explanation

To find the number of moles of ions which 1 mol of ionic compound produces on being dissolved in water, we must calculate the valve of van't hoff factor (i). We have
`DeltaT_(f)=iK_(f)m`
or `i=(DeltaT_(f))/(K_(f)m)`
`=((0.00732^(@)C))/((1.86^(@)C//m)(0.0020 m))`
`=1.968`