Question: what is the difference between concentrated hcl and dilute hcl?
Answer: Dilute acids will be, for example, 80 or 90% water, with only 10 - 20% of the weight being the acid itself. ... Concentrated hydrochloric acid is 37% HCl (HCl itself is a gas, so 37% w/w is about the maximum you can dissolve in water).