Given below is the chemical reaction responsible for removing the temporary hardness of water
`C a (HCO _(3)) _(2) + Ca ( OH) _(2) to Ca CO _(3) + H _(2) O `
(unbalanced)
What amount of `Ca(OH)_(2)` in gram required to produce 5. 9 g of equimolar mixture of calcium carbonate and water.

Options

A. `1. 85 g`
B. `3. 25 g `
C. `5. 92 g `
D. `0. 05 g `

Answer

A

Explanation

Let moles of `Ca CO _(3) = a `
then moles of `H _(2) O = a `
(a)` (100 ) + (a) (18) = 5.9 `
`118 a = 5.9`
` a = 0.05`
`Ca (HCO _(3)) _(2) + Ca ( OH ) _(2)`
`to 2 Ca CO _(3) + 2 H _(2) O `
moles of `Ca (OH ) _(2) = (0.05)/(2)`
moles of
`Ca ( OH ) _(2) = ( 0.05)/(2) xx 74 = 1. 85 g`