0.0001M(10-4M) HCl. mix 5 mL of 0.1M hydrochloric acid, HCl,into 45 mL of distilled water (the water need not be boiled) to make 50mL of 0.01M HCl.take 5mL of the0.01 M HCl and mix it with another 45mL of water to make 50 mL of 0.001 M HCl. stir.finally, take 5mL of the 0.001 M HCl and mix it with another 45 mL of water to make 50 mL of 0.0001 M HCl. stis. this called progressive dilution-a preferred technique for preparing very dilute solutions