Answer: sorry i dont knowExplanation:
 
        
             
        
        
        
You have already gotten the balanced equation. And the ratio of mol number of reactants and production is the ratio of coefficient. So there is 6.4/8*11=8.8 mol oxygen needed. The mass is 8.8*32=281.6 g.
        
             
        
        
        
Answer:
The answer to your question:  0.7 M
Explanation:
Data
V of KOH = 90 ml
[KOH] = ?
V H2SO4 = 21.2 ml
[H2SO4] = 1.5 M
                        2KOH(aq)  +  H₂SO₄(aq)   →   K₂SO₄(aq)  +  2H₂O(l)
Molarity = moles / volume
moles of H₂SO₄ = (1.5) (21.2)
                            = 31.8 
                     2 moles of KOH --------------  1 mol of H₂SO₄
                    x                           --------------  31.8 mol of H₂SO₄
                     x = (31.8)(2) / 1
                     x = 63.8 moles of KOH
Molarity = 63.8 / 90
              = 0.7 M