[spirochete]

Why is it ideal to have a titration volume of about 40 ml if using a 50 ml burette?

One obvious reason would be that a larger volume would require refilling the burette during the titration, which would mean you'd have to do a few extra calculations when you're done.

But that still leaves the question of why a smaller volume wouldn't work just as well, say for example under ten ml.  In this case you'd end up with one less significant figure in your reading, getting 3 instead of the four you'd get if reading above ten ml.

But if that's the full answer than anything above 10 ml would work fine, and the question would be worded differently.

That is all I can think of.  What am I missing here?

[Borek]

Think about relative accuracy. Volume reading error is always the same.

[spirochete]

oh so using the largest possible volume minimizes percent error?

So in principle it would be better to use an even larger burrette?  You would just need to stand on a ladder to read it. . .

[Borek]

oh so using the largest possible volume minimizes percent error?

So in principle it would be better to use an even larger burrette?  You would just need to stand on a ladder to read it. . .

Not exactly. Smaller burettes can measure smaller volumes, but with larger accuracy. Relative accuracy doesn't change much.

[spirochete]

So you're saying you have to consider both the intrinsic accuracy of the burette as well as relative error?

But all other things equal, it's better to use a larger volume.