0.4 mole of orthophosphoric acid and 1.0 mole of calcium hydroxide were allowed to react. Calculate the maximum number of moles of calcium phosphate formed. 

Explanation

The stoichiometric equation is
`3Ca(OH)_(2)+2H_(3)PO_(4)rarr Ca_(3)(PO_(4))_(2)+3H_(2)O`
`"3 moles of "Ca(OH)_(2) = 2" moles of "H_(3)PO_(4)`
`"1 mole of "Ca(OH)_(2) = 0.67" mole of "H_(3)PO_(4)`
`"0.6 mole of "Ca(OH)_(2) = 0.4 mole of "H_(3)PO_(4)`
`H_(3)PO_(4)` is the limiting reagent. Hence, salt formed is dependent on the availability of acid only.
`"2 moles of "H_(3)PO_(4) = 1" mole of "Ca_(3)(PO_(4))_(2)`
`"0.4 moles of "H_(2)PO_(4) = ?`
Number of moles of calcium phosphate formed `=0.4xx(1)/(2)="0.2 mole"`