Question

Concentrated hydrochloric acid has specific gravity 1.18 and 36% hcl weight. What volume of concentrated hcl must be diluted to give 50gm of 10 percent

My calculation

50gm x 10% = 5gm
5gm x 36.46 =182.3/ 0.36 =
506 / 1.18 = 429 ml

I am not sure answer. Who helps me to solve it for me. Thank you.

Answer 1

I worked this for you a day or so ago (two ways in fact) so you should know 429 mL is not right.In the future I will ignore any problems I've addressed previously.
g x % = g x %
50g x 10% = g x 36%
g = (50*10/36) = 13.89g.
Use density = mass x volume to convert 13.89g to mL.
v = m/d = 13.89/1.18 = 11.77 mL which I would round to 11.8 mL.

You can prove this is right as follows:
1.18g/mL x ?mL x 0.36 = 5g
?mL = 11.77

The other way to do this is by parts.
You want to dilute from 36^ to 10% which is a factor of 36/10 = 3.6. Therefore, you want to dilute 1 part acid with 2.6 parts water to make the solution. How much is 1 part? That's 50g/3.6 = 13.89 g which converts to 11.77 mL.