[delicate_tears]

In an experiment 20.00 ml of HCl was standardised by titration with a solution of .104M  sodium carbonate. The average titre of sodium carbonate was 11.60 ml. Write an equation for the reaction and determine the concentration of the hydrochloric acid solution.

SO, my Question is: is the unkwon solution always has to be in the burette? Does it matter if it's an acid or a base?

[Borek]

Quite the opposite - usually in the burette is solution of known concentration, called titrant.

Doesn't matter what it is - what matters is stoichiometry of the reaction.

http://www.titrations.info/titration-calculation