Use the formula stated below

So
#H_3PO_4

#Ba(OH)_2

Hence H_3PO_4 is the limiting reagent
To solve the question you use the following formula:
concentration (1) × volume (1) = concentration (1) × volume (1)
3 M × volume (1) = 1.8 M × 50 mL
volume (1) = (1.8 M × 50 mL) / 3 M = 30 mL
True would be your answer
<span>Double-replacement and acid-base reactions are examples of redox reactions.
</span><span>b. false</span>