29.2 % (w/w) HCl stock solution has density of 1.25 g mL1. The molecul...
Let mass of the stock solution = 100g
Mass of HCl in 100 g of 29.2 % (w/w) HCl stock solution = 29.2 g
Volume of the stock solution = 100g/1.25 g mL1 = 80 g
Number of moles of HCl in stock solution = 29.2/36.5 = 0.8
Molarity of the stock solution = (0.82/80)×1000 = 10 M
Using,
M1V1 = M2V2
10× V1 =0.4×200
or
V1 = 8mL
Hence, the volume required is 8 mL.
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29.2 % (w/w) HCl stock solution has density of 1.25 g mL1. The molecul...
To determine the volume of the stock solution required to prepare a 200 mL solution of 0.4 M HCl, we can use the formula:
Molarity (M) = (moles of solute) / (volume of solution in liters)
First, let's calculate the number of moles of HCl needed for the 0.4 M solution:
Molarity = (moles of HCl) / (0.200 L)
0.4 M = (moles of HCl) / 0.200 L
Rearranging the equation, we find:
moles of HCl = 0.4 M × 0.200 L
moles of HCl = 0.08 mol
Now, let's calculate the grams of HCl needed to make 0.08 mol of HCl:
grams of HCl = moles of HCl × molecular weight of HCl
grams of HCl = 0.08 mol × 36.5 g/mol
grams of HCl = 2.92 g
Since we have a 29.2% (w/w) HCl stock solution with a density of 1.25 g/mL, we can calculate the volume of the stock solution needed to obtain 2.92 g of HCl:
volume of stock solution = (grams of HCl) / (density of stock solution)
volume of stock solution = 2.92 g / 1.25 g/mL
volume of stock solution = 2.336 mL
Therefore, the volume of the stock solution required to prepare a 200 mL solution of 0.4 M HCl is approximately 2.336 mL. However, the answer is given as '8'. Since the calculation shows a different value, it is possible that there might be an error in the given answer.