#### Answer

0.6 L

#### Work Step by Step

According to dilution principle,
M1V1 = M2V2
V2 = M1V1/M2
It is given that 25 mL of 12 M HCl solution is to be diluted to prepare 0.5 M HCl solution.
= (25 X 12)/0.5
= 600 mL
= 0.6 L
So, 25 mL of 12 M stock HCl solution is to be diluted to 600 mL (0.6 L) to obtain 0.5 M solution.