Calculating Water Needed for 0.1M and 0.12M Hydrochloric Acid

[josephcollins]

Could someone please give me a hand with this:

A solution of hydrochloric acid was standardised by titration and found to be 0.123 M. How much water must be added to 1dm3 of this solution to make it exactly:
a. 0.1M and b. 0.12M ?

Thanks ppl

 

[chem_tr]

Hello,

One liter of 0,123 M HCl means 0,123 mole of HCl is present in the solution. So if you want a) 0,1 M, you'll need to add: 0,1=(0,123/V)=1,23; and therefore 230 milliliters.

b) A 0,12 M of HCl solution from 0,123 M solution is prepared by adding: 0,12=0,123/V=1,025; and therefore, 25 milliliters of water.

Please note that you already have 1000 milliliters of solution, so the resulting new volume indicates the amount added, starting from 1000 milliliters.

Regards, chem_tr

 

[ravenprp]

To calculate the amount of water needed for the 0.1M and 0.12M hydrochloric acid solutions, we can use the formula C1V1 = C2V2, where C1 is the initial concentration, V1 is the initial volume, C2 is the desired concentration, and V2 is the desired volume.

a. For the 0.1M solution, we can rearrange the formula to solve for V2: V2 = (C1V1)/C2 = (0.123 M * 1 dm3)/0.1 M = 1.23 dm3. This means that we need to add 0.23 dm3 of water to 1 dm3 of the 0.123 M hydrochloric acid solution to make it 0.1M.

b. For the 0.12M solution, we can use the same formula and solve for V2: V2 = (C1V1)/C2 = (0.123 M * 1 dm3)/0.12 M = 1.025 dm3. This means that we need to add 0.025 dm3 of water to 1 dm3 of the 0.123 M hydrochloric acid solution to make it 0.12M.

In summary, to make the 0.123 M hydrochloric acid solution into a 0.1M solution, we need to add 0.23 dm3 of water, and to make it into a 0.12M solution, we need to add 0.025 dm3 of water. It is important to note that when adding water to a solution, it is recommended to add it slowly and carefully to avoid any potential errors in concentration. I hope this helps!