1) Na2CO3 +2HCl==2NaCl+H2O+CO2↑
106/x = 44/2.2
x = 5.3
2) 9.3-5.3=4
4/9.3=43%
3)5.3×23×2/106=2.3
4×23/40=2.3
(2.3+2.3)÷23/58.5=11.7g
11.7÷(9.3+50-2.2)×100%≈20.5%
4)11.7×35.5/58.5=7.1
7.1÷35.5/36.5=7.3
7.3÷50×100%=14.6%