Дано
m(H3PO4)=196 kg= 196000 g
m(NaOH)=200 kg=200000g
-------------------------------------
V(H2O)-?
196000 200000 X L
H3PO4+3NaOH-->Na3PO4+3H2O
3*40 3*22.4
M(H3PO4)=98 g/mol
M(NaOH)=40 g/mol
Vm=22.4L/mol
n(H3PO4)=m/M=196000/98=2000 mol
n(NaOH)=m/M=200000*40=5000 mol
n(H3PO4)>n(NaOH)
200000/120 = X/67.2
X=112000 л
ответ 112000 л