Titration problem
Hey guys, can someone help me with this
Calculate how many grams of potassium hydroxide are needed to fully titrate 450 mL of a solution obtained by dissolving 1.9 g of phosphoric acid in 1500 mL of aqueous solution. (Molar masses: H-1 g/mol, O-16 g/mol, P-31 g/mol, K-39 g/mol)
I tried firstly calculating the moles of phosphoric acid used, and then I wanted to use M1V1=M2V2 to find the mole later and then just multiply with Mr to get the mass, but I think I am doing a mistake in here cause I don’t even enough data to use that equation, but I can’t think of any other method either.
Calculate how many grams of potassium hydroxide are needed to fully titrate 450 mL of a solution obtained by dissolving 1.9 g of phosphoric acid in 1500 mL of aqueous solution. (Molar masses: H-1 g/mol, O-16 g/mol, P-31 g/mol, K-39 g/mol)
I tried firstly calculating the moles of phosphoric acid used, and then I wanted to use M1V1=M2V2 to find the mole later and then just multiply with Mr to get the mass, but I think I am doing a mistake in here cause I don’t even enough data to use that equation, but I can’t think of any other method either.
Bump
Original post by Roha125
My fav human, thank you
Original post by Roha125
I think you are missing a step, since it tells you in the question that only 450 ml of the 1500 ml of solution is used.
Your calculation assumes that all 1500 ml is used, so how might you refine your answer in light of this?
Original post by TypicalNerd
I think you are missing a step, since it tells you in the question that only 450 ml of the 1500 ml of solution is used.
Your calculation assumes that all 1500 ml is used, so how might you refine your answer in light of this?
Your calculation assumes that all 1500 ml is used, so how might you refine your answer in light of this?
I tried doing like this but for the step in which I highlighted in pink, I was hesitant to multiply by 3 for the KOH, because usually we multiply only when we have moles right? But In this case I couldn’t find any other way to do it.
Original post by Ailurophile03
I tried doing like this but for the step in which I highlighted in pink, I was hesitant to multiply by 3 for the KOH, because usually we multiply only when we have moles right? But In this case I couldn’t find any other way to do it.
Multiplying by 3 is correct, because KOH reacts in a 3:1 ratio.
Usually, you’d calculate the moles of H3PO4 in the portion of the solution used before scaling up by a factor of 3. Essentially what you’ve done is the correct steps in a slightly different order, so your method does work.
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