How many mL of 12M HCl is needed to create 350mL of 0.125M HCl?

x ml of 12M HCl = 12x milimoles

350 ml of 0.125M HCL = 43.75 milimoles

43.75=12x
x=3.6458

I agree with Shubh but s/he used too many significant figures in the result. You're allowed two places (from the 12M number)[that's assuming the post did not omit zeros after the 12]. So I would round to 3.6 mL. If that is REALLY 12.0 M then I would round to 3.65 mL.

To determine the volume of 12M HCl needed to create 350mL of 0.125M HCl, we can use the formula:

(M1)(V1) = (M2)(V2)

Where:
M1 = initial molarity
V1 = initial volume
M2 = final molarity
V2 = final volume

Given:
M1 = 12M
V1 = ?
M2 = 0.125M
V2 = 350mL

Rearranging the formula, we get:

V1 = (M2)(V2) / M1

Plugging in the given values:

V1 = (0.125M)(350mL) / 12M

Simplifying the calculation:

V1 = 3.125mL

Therefore, approximately 3.125mL of 12M HCl is needed to create 350mL of 0.125M HCl.