Volumetric analysis

[Over9000]

Mass of lawn fertiliser: 1.301g

Here are the steps to the prac

1. Using a small funnel, carefully transfer the sample of the fertiliser to the volumetric flask (250mL). Add water until it reaches the calibration line (250mL).

2. Using a 20.00mL pipette, dispense aliquots of the fertiliser solution into each of the 3 conical flasks.

3. Thoroughly wash the pipette and rinse it with a small volume of standard sodium hydroxide solution. Place a 20.00mL aliquot of NaOH solution in each of the flasks containing fertiliser solution. The NaOH solution has a concentration of 0.1M

4. Rinse and fill a burette with standard hydrochloric acid, concentration is 0.09933M

5. add 4-6 drops of methyl red indicator to each conical flask containing the fertiliser solution and titrate.

The average titre i got was 16.335mL

How would the titre change if Sulfuric acid was used instead of HCl??

[TrueTears]

The final titre would half.

[Over9000]

Why would the titre half, if its a weaker acid

[TrueTears]

The problem here is we have to write a new equation:

( i left out the states)

so

now, i assume this is from the SAC that you have to do soon, so i shall use my results i got from my prac.(you can check my thread for the details)

Now assuming concentration of NaOH is the same as HCl used, ie 0.09933M

and assuming we need the same amount of NaOH as before, ie 0.00162256 mol

sub these values in (i let x be the titre in mL)

solving for x yields 8.1675 mL, the titre i got when using HCl from the prac was 16.335mL

so

therefore the new titre is half of the original, ie halved.