Chapter SH, Problem 18.1APP

To determine

To Establish:The formula of the compound when ammonium ions $\left({\text{NH}}_4^{+}\right)$ and phosphate ions $\left({\text{PO}}_4^{3-}\right)$ combine.

Answer to Problem 18.1APP

When ammonium ions $\left({\text{NH}}_4^{+}\right)$ and phosphate ions $\left({\text{PO}}_4^{3-}\right)$ combinethe formula of the compound formed is ${{\text{(NH}}_4\text{)}}_3{\text{PO}}_4$ .

Explanation of Solution

Introduction:

In the compound:

The positive ion is ammonium $\left({\text{NH}}_4^{+}\right)$ , having oxidation number $1+$

The negative ion is phosphate: $\left({\text{PO}}_4^{3-}\right)$ , having oxidation number $3-$

First write the symbol of the element having positive charge followed by the symbol of the element having negative charge.

  ${\text{NH}}_4^{+}{\text{PO}}_4^{3-}$

Without the sign, one ion’s charge forms the subscript of the other. One must use parentheses before writing the subscript.

  ${{\text{(NH}}_4\text{)}}_3{\text{PO}}_4$

In this case, the subscripts already are the lowest whole numbers that maintain the ratio of the ions.

Conclusion:

When ammonium ions $\left({\text{NH}}_4^{+}\right)$ and phosphate ions $\left({\text{PO}}_4^{3-}\right)$ combine the formula of the compound formed is ${{\text{(NH}}_4\text{)}}_3{\text{PO}}_4$ .