[Diva]

Calculate the concentration of the hydrochloride acid if a 15mL sample (diluted by factor of 10) is titrated with standard sodium carbonate solution. The titration required 10mL of 0.250 mol per L sodium carbonate to neutralize the acid?

Need *delete me*

[Arkcon]

Greetings, Diva:, I can see that you're new, and I'd like to welcome you to the Chemical Forums.  I'd like to remind you to read our Forum Rules{click}.  You agreed to these rules as a condition of signing up for our forum, and they apply to you, whether you agree with them or not, or even if you're unaware of them.

You're going to need a balanced chemical reaction.  So go ahead and write it for us.  You're going to have to write down that dilution step, so you don't forget it -- after dilution, how much is actually there?  How much sodium carbonate is there in that volume of that concentration sodium carbonate?

Need *delete me*

My hints should start you on your way.

[Diva]

2HCL + Na2CO3 --> 2NaCl + CO2 + H2O
 Ratio 2:1

[Borek]

How many moles of carbonate?