How many milliliters of 0.20 molar koh solution are needed to exactly neutralize 20. milliliters of 0.50 molar hcl?

The balanced equation for the neutralisation reaction between KOH and HCl is as follows
KOH + HCl --> KCl + H₂O
stoichiometry of KOH to HCl is 1:1
the number of HCl moles reacted = HCl concentration x volume 
number of HCl moles = 0.50 mol/L x 0.020 L = 0.01 mol
according to molar ratio of 1:1
number of KOH moles required to neutralise 0.01 mol of HCl = 0.01 mol of KOH
molarity of KOH = 0.20 M
there are 0.20 mol in 1 L Then 0.01 mol are - 0.01 mol / 0.20 mol/L = 50 mL 
50 mL of 0.20 M KOH required 

A. is your answer.  hope this  

for left side: 3 c, 8 h, 2 o. for right side, 1 c, 3 o, 2 hwe want to balance oxygen last because it is the only one that is isolated. we can fine tune it at the end.put a coefficient on right side to balance the number of carbons.now make the number of hydrogens eventhere are 8 h on the left and 2 h on the right. put a coefficient on the right side like so: now we have 10 oxygens on the right and 2 on the left. to get the left side to have 10 oxygens, put a coefficient of 5 (5 * 2 = 10)the coefficient in front of  in the balanced equation is 3.