How can I prepare 0.3M H3PO4 in 250 ml dis water

How many moles do you need? That's mols = M x L = 0.3 x 0.250

How many grams is that? That's mols = grams/molar mass = ? You know molar mass and mols, solve for grams.

To prepare a 0.3M H3PO4 (phosphoric acid) solution in 250 ml of distilled water, you will need to follow these steps:

1. Calculate the amount of H3PO4 needed:
Since you want to prepare a 0.3M solution, this means you need 0.3 moles of H3PO4 per liter (1000 ml) of solution.
Therefore, to calculate the moles needed for 250 ml, you can use the formula:
Moles = Molarity (M) × Volume (L)

Moles = 0.3 mol/L × 0.250 L
Moles = 0.075 moles

2. Determine the molecular weight of H3PO4:
Phosphoric acid (H3PO4) consists of three hydrogen atoms, one phosphorus atom, and four oxygen atoms.
The atomic masses are as follows:
H (Hydrogen) = 1 g/mol
P (Phosphorus) = 31 g/mol
O (Oxygen) = 16 g/mol

So, the molecular weight of H3PO4 is:
3 × 1 g/mol (for hydrogen) + 1 × 31 g/mol (for phosphorus) + 4 × 16 g/mol (for oxygen)
Molecular weight = 98 g/mol

3. Calculate the grams of H3PO4 needed:
To find the grams of H3PO4 required, we can use the formula:
Grams = Moles × Molecular Weight

Grams = 0.075 moles × 98 g/mol
Grams = 7.35 grams

4. Weigh out 7.35 grams of H3PO4:
Use a balance or scale to measure out 7.35 grams of phosphoric acid powder accurately.

5. Dissolve the weighed H3PO4 in 250 ml of distilled water:
Pour the 250 ml of distilled water into a container big enough to hold both the water and the solute (H3PO4).
Slowly add the weighed H3PO4 into the water while stirring continuously until it is completely dissolved.

6. Transfer the solution to a suitable container:
Once the H3PO4 is fully dissolved, transfer the solution to a suitable container with a tight-fitting lid. Label the container as 0.3M H3PO4 for proper identification.

Remember to handle the phosphoric acid with care as it is corrosive. Always wear appropriate personal protective equipment, such as gloves, goggles, and an apron, while handling chemicals. Also, ensure that you work in a well-ventilated area.

If you are not comfortable with chemical handling or do not have access to the required equipment, it is advisable to seek assistance from a qualified individual or purchase a ready-made solution.