1.
If 0.5mol0.5\,\text{mol} of BaCl2\text{BaCl}_2 is mixed with 0.2mol0.2\,\text{mol} of Na3PO4\text{Na}_3\text{PO}_4, the maximum number of moles of Ba3(PO4)2\text{Ba}_3(\text{PO}_4)_2 that can be formed is:

3BaCl2+2Na3PO4Ba3(PO4)2+6NaCl3\text{BaCl}_2 + 2\text{Na}_3\text{PO}_4 \longrightarrow \text{Ba}_3(\text{PO}_4)_2 + 6\text{NaCl}