Question

Se amesteca 200g solutie HCl 10% cu 600g solutie HCl 30% cu 200g H2O. Solutia obtinuta se neutralizeaza cu soda caustica. Se cere:
a. Concentratia finala
b. Cantitatea de soda caustica 40% necesara neutralizării acidului
c. Concentratia sarii utilizate

Answer 1

C1=md1/ms1*100 => md1=C1*ms1/100 = 10*200/100 = 20g

C2=md2/ms2*100 => md2=30*600/100 = 180g

mdf = md1+md2 = 200g
msf = ms1+ms2+mH2O = 1000g sol

a. Cf=mdf/msf*100 = 200/1000*100 = 20%

b. HCl + NaOH => NaCl + H2O

36,5g HCl...............40g NaOH
200g HCl................x= 219,178g (md)

C=md/ms*100 => ms=md*100/C = 21917,8/40 = 547,945g sol. NaOH

c. msf = 1000+547,945 = 1000+547,945 = 1547,9452g sol

C=md/msf*100 = 320,5479/1547,9452*100 = 20,7%

Nu sunt sigur la subpunctul c.. Nu cred ca am facut bine..