A prescription calls for 250ml of a 0.1N hydrochloric acid HCL solution. How many ml of concentrated hydrochloric acid are needed to make this solution? The specific gravity hydrochloric acid is 1.18 the molecular weight is 36.46 and the concentration is 37.5% because hydrochloric acid function as an acid and react giving up one proton in a chemical reaction, 1 Eq is contained in each mole the compound. This the equivalent weight is 36.46g.
My calculation:
250ml x 0.1N changes 0.25L x 0.1 = 0.025meq.
0.025 x 36.46 = 0.9115gm
Thus 1gm of pure HCL is contained 100gm/37.5 = 2.66gm
And then 0.9115 x 2.6gm /1.18 = 2.01gm
Who tells me the right answer. My own answer is 2.01gm. Please helps me.
The problem asks for mL of the concentrated acid; you calculated grams.
N acid = 1.18 x 1000 x 0.375 x (1/36.46) = about 12.14 N
Then 12.14 x ?mL = 250 x 0.1
Solve for ?mL. I obtained 2.06 mL which corresponds to 2.06*1.18 = 2.43 g.
To calculate the amount of concentrated hydrochloric acid needed to make a 250 ml solution of 0.1N hydrochloric acid, you can follow these steps:
1. Determine the amount of hydrochloric acid in moles needed for the solution.
250 ml x 0.1 N = 0.025 moles
2. Calculate the mass of hydrochloric acid needed using the equivalent weight.
0.025 moles x 36.46 g/mol = 0.9115 grams
3. Convert the mass to grams of concentrated hydrochloric acid by considering its concentration and specific gravity.
To do this, you first need to determine the number of grams of pure HCl in 100 grams of the concentrated solution.
37.5% concentration means that there are 37.5 grams of HCl in 100 grams of solution.
So, 1 gram of concentrated HCl contains 1 gram / 37.5 = 0.0267 grams of pure HCl.
Next, multiply the pure HCl mass by the specific gravity to account for the difference in density between the concentrated acid and pure HCl.
0.9115 grams x (0.0267/1.18) = 0.02058 grams of concentrated hydrochloric acid
Therefore, the correct answer is approximately 0.02058 grams (or 20.58 mg) of concentrated hydrochloric acid.