Answer:
I think it is [ (b) 18 ml]
Step-by-step explanation:
Let's
V1 : The volume of (HCl)
M1 : The........ of ( HCl)
V2 : The volume of (NaOH)
M2 : The....... of ( NaOH)
V1 * M1 = V2 * M2
45 * 0.20 = V2 * 0.50
V2 = 9/0.5
V2 = 18 ml
I hope that is useful for you :)