Question

Balance the following reaction. A coefficient of "1" is understood. Choose option "blank" for the correct answer if the coefficient is "1." Ca(OH)2 + H3PO4 → Ca3(PO4)2 + H2O

Answer 1

 The balanced equation for

 Ca(OH)2  +  H3PO4→  Ca3(PO4)2  +  H2O    is

 3 Ca(OH)2  +2 H3PO4→  Ca3(Po4)2  +  6  H2O

3 moles of  Ca(OH)2  reacted with 2  moles of H3PO4  to  form  1 mole  of  Ca3(PO4)2   and  6  moles  of H2O

Answer 2

Explanation:

A balanced equation is the one which contains equal number of atoms on both reactant and product side.

For example, $Ca(OH)_{2} + H_{3}PO_{4} \rightarrow Ca_{3}(PO_{4})_{2} + H_{2}O$

Number of atoms on reactant side are as follows.

• Ca = 1

• O = 6

• H = 5

• P = 1

Number of atoms on product side are as follows.

• Ca = 3

• O = 9

• H = 2

• P = 2

Therefore, to balance the chemical equation multiply $Ca(OH)_{2}$ by 3 and multiply $H_{3}PO_{4}$ by 2 on reactant side. Whereas multiply $H_{2}O$ by 6 on product side.

Hence, the balanced chemical equation will be as follows.

       $3Ca(OH)_{2} + 2H_{3}PO_{4} \rightarrow Ca_{3}(PO_{4})_{2} + 6H_{2}O$