if 50ml of a sample of hard water consumed 15 ml of 0.01M-EDTA.what is the hard ness of water
Well, it seems like the water is pretty tough! I mean, consuming 15 ml of EDTA? That's quite a gulp! But, let's get down to the calculations.
The hardness of water can be determined by the amount of EDTA required to titrate it. In this case, you used 15 ml of 0.01M EDTA solution.
To find the hardness, we need to use the formula:
Hardness (in mg/L) = (Volume of EDTA used in ml) x (Molarity of EDTA) x (1000 ml/L)
Plugging in the values, we get:
Hardness = (15 ml) x (0.01 M) x (1000 ml/L) = 150 mg/L
So, the hardness of the water sample is 150 mg/L. Keep in mind that water hardness can vary, just like a clown's sense of humor!
To determine the hardness of the water sample, we need to calculate the concentration of calcium and magnesium ions present in the water.
1. First, we calculate the number of moles of EDTA (ethylenediaminetetraacetic acid) used in the titration:
Moles of EDTA = volume of EDTA (in L) * concentration of EDTA (in mol/L)
Moles of EDTA = 0.015 L * 0.01 mol/L
Moles of EDTA = 0.00015 mol
2. EDTA reacts with calcium and magnesium ions in a 1:2 molar ratio. Since the volume of the water sample used is 50 mL (0.05 L), which is half of the volume used for the titration, we can calculate the concentration of total calcium and magnesium ions.
Concentration of total calcium and magnesium ions (in mol/L) = Moles of EDTA / volume of water sample (in L)
Concentration of total calcium and magnesium ions = 0.00015 mol / 0.05 L
Concentration of total calcium and magnesium ions = 0.003 mol/L
3. The concentration of calcium ions is determined from the molar mass of calcium (40.08 g/mol) and the 1:2 molar ratio with EDTA.
Concentration of calcium ions (in mol/L) = Concentration of total calcium and magnesium ions * (molar mass of calcium / molar mass of EDTA)
Concentration of calcium ions = 0.003 mol/L * (40.08 g/mol / 292.24 g/mol)
Concentration of calcium ions ≈ 0.000412 mol/L
4. To convert the concentration of calcium ions to ppm (parts per million) as CaCO3, we multiply by the molar mass of calcium carbonate (100.09 g/mol).
Hardness of water (in ppm as CaCO3) = Concentration of calcium ions * molar mass of CaCO3
Hardness of water ≈ 0.000412 mol/L * 100.09 g/mol
Hardness of water ≈ 0.0412 g/L
Therefore, the hardness of the water sample is approximately 0.0412 g/L or 41.2 ppm as CaCO3.
To calculate the hardness of water based on the given information, we need to understand the principle behind the reaction between hard water and EDTA (Ethylenediaminetetraacetic acid).
EDTA is a complexing agent that forms a stable complex with metal ions, including calcium (Ca2+) and magnesium (Mg2+), which are the main components of water hardness. The reaction equation is as follows:
Ca2+ (or Mg2+) + EDTA → [Ca(EDTA)]2- (or [Mg(EDTA)]2-)
In the given question, 50 ml of a hard water sample consumed 15 ml of 0.01 M EDTA. From this information, we can find the number of moles of EDTA used.
First, calculate the number of moles of EDTA:
Moles of EDTA = Molarity × Volume (in liters)
= 0.01 mol/L × 0.015 L
= 0.00015 mol
Since the ratio of 1 mole of EDTA reacts with 1 mole of Ca2+ or Mg2+, we can assume that the number of moles of Ca2+ (or Mg2+) present in the water sample is also 0.00015 mol.
Now, to find the hardness of water, we need to convert the moles of Ca2+ (or Mg2+) to their respective units. The hardness of water is often expressed in terms of calcium carbonate equivalents (CaCO3).
1 mol of Ca2+ (or Mg2+) = (molar mass of CaCO3)/(molar mass of Ca2+ (or Mg2+))
1 mol of CaCO3 = 100 g (approximately)
Using the molar masses:
Molar mass of CaCO3 = 40 g/mol
Molar mass of Ca2+ (or Mg2+) = 40 g/mol
Hardness of water (as CaCO3) = (0.00015 mol × 100 g/mol) / (50 mL × 0.001 L/mL)
= 0.03 g/L
Therefore, the hardness of water is 0.03 g/L as calcium carbonate equivalents (CaCO3).
Moles of ETDA=.015*.01=1.5e-4
assuming moles ETDA=moles Hardness
grams CaCO3= it is 1.5e-4*100=.015 g/liter or 15mg/liter or 15ppm