Get the net ionic equation for na2co3 + 2hcl = co2 + h2o + 2nacl.

 Na2CO3 + 2HCl = CO2 + H2O + 2NaCl
this is the double displacement reaction
2 Na(+)  +  CO3(-2)  +  2H(+)  + 2Cl(-) >  2Na(+) + 2 Cl(-) + H2O + CO2
2Na+ and 2Cl- are the spectator ions as they appear on the both sides of equation :
so the net ionic equation can be written as :
CO3(-2)  +  2H(+) > H2O + CO2

29.1-12=17.1the answer is this one

257 grams h2o i think