Question

100 g de soluție de hidroxid de sodiu cu concentrația 20% reactioneaza cu o salutie de acid clorhidric de concentrările 20%. Calculati masa de acid clorhidric rezultat si cantitatea de sare

Answer 1

C=md/ms*100 => md=C*ms/100=20*100/100=20g NaOH

MNaOH=ANa+AO+AH=23+16+1=40g/mol

MHCl=AH+ACl=1+35,5=36,5g/mol

MNaCl=ANa+ACl=23+35,5=58,5g/mol

NaOH + HCl => NaCl + H2O

40g NaOH................36,5g HCl
20g NaOH................x=18,25g HCl

C=md/ms*100 => ms=md*100/C=18,25*100/20=91,25g sol. HCl

40g NaOH.....................58,5g NaCl
20g NaOH.....................x=29,25g NaCl

n=m/M=29,25/58,5=0,5 moli NaCl (sare de bucatarie)