Question

500 cm3 of 0.1 M HCL= how many moles of HCL

Answer 1

How do I make a 1 M HCl solution become a 0.1 M solution?
You see the concentration decreased ten fold, from 1 M to 0.1 M.

You can simply increase the volume by ten times.

For example

If you have 250 mL of 1 molar HCl, you can add distilled water upto 2500 mL. Now the concentration is 0.1 molar.

If you want to use the serial dilution method, you can use the C1V1=C2V2 equation.

C1 = starting concentration.
C2 = final concentration.

V is for volume.

So let's say you have 500 mL of 1 M HCl and you only want 50 mL of 0.1 M HCl.

1 M x V1 = 0.1 M x 50 mL
V1 = 5 mL

So you take 5 mL of the original (stock) solution and dilute it up to 50 mL. Then you have 50 mL of 0.1 M HCl.

Answer 2

0.1*500*0.001=0.05 mole