sodium hydroxide
TRANSCRIPT
Properties of (NaOH)
Physical
☻It is solid substant has a white color.
☻Dissolve easily in water and give a high heat.
☻It is substant (Absorb moisture from atmosphere).
Chemical
☻React with acids {HCL, H2SO4} and acidic oxide {CO2, SO2}
(Acids)→NaOH+HCl NaCL+H2o
(Acids)→ NaOH (solu) +H2SO4 NaHSO4+H2o
(Acidic oxide)→ NaOH (solu) + CO2 NaHCO3
NaHCO3 +NaOH Na2CO3+H2o
(Acidic oxide)→ NaOH (solu) +So2 NaHSO3
NaHSO3 +NaOH Na2SO3+H2o
FOR NOTE: If we use {NaOH (molten)} the rate of reaction will increase but depend
On the kind of salt.
☻React with salt solution and amphoteric salt
→ 2NaOH+ CuSo4 Na2SO4 +Cu (OH) 2 ↓
→ 6NaOH + Fe2 (SO4)3 3Na2SO4 +2Fe (OH) 3 ↓
(Amphoteric salt)→ 6NaOH+AL2(SO4)3 3Na2SO4 +2AL(OH)3↓
→ NaOH+ 2AL(OH)3 NaALO2 +2H2O
FOR NOTE: (SODIUM META ALUMINATE) is {NaALO2}
(Ammonium salt)→ NaOH+NH4CL NaCL + NH4OH
NH4OH (heat)
NH3 + H2O
FOR NOTE: The last reaction is reversible so that it necessary to heat it to give that
Product (NH3).
☻React with element
React with non-metal and product depends on the temp.of solu. .
→ (with chloride gas on cold)
→ CL2 +H2O HCL+HCLO
NaOH+HCL NaCL + H2O
NaOH +HCLO NaCLO +H2O
CL2 +2 NaOH (solu) NaCLO+NaCl+H2O
FOR NOTE: NaCLO {sodium hypochlorite}
HCLO {hydrochloride}
→ (with chloride gas on heating)
→ 3CL2 +3H2O 5HCL+HCLO3
5NaOH+5HCL 5NaCL +5H2O
NaOH +HCLO3 NaCLO3 +H2O
3CL2 +6 NaOH 5NaCL +NACLO3+3H2o
React with amphoteric metal like (AL, Zn, and Pd):
→ 3NaOH (fuse) + AL Na3ALO3+3/2 H2
↓
{Sodium aluminates}
FOR NOTE: the hot solution will make the reaction very slowly so that we use fused
(NaOH) with such metals to make it very rapid
Uses of sodium hydroxide
☻ In paper industry where it dissolve lignine {which holds the fibers wood together}.
☻ In tanning of leather where it dissolves the binding material between the fibers .
☻ In petroleum product where it clear it .
☻ In organic where it favored the artificial fibers (viscose) and natural (cellulosic) .
☻ In making a shine layer.
☻The main field of uses of it is {soap} and {glycerol}
CH2 – COOR + NaOH CH2-OH
│ │
CH – COOR + NaOH CH-OH + 3RCOONa
│ │
CH2 – COOR + NaOH CH2-OH
↓ ↓ ↓ ↓
{Ester of a {caustic {glycerol} {soap}
Tribasic soda}
Organic acid} → like (plamitic, stearic, oleic acid)
Industrial preparation
☻NaOH is prepared by electrolysis of a brine solution in a cell having graphite anode
and a cathode made from platinum:
NaCL (solution) Na++CL
-
At anode 2CL- CL2+2e
At cathode Na+
+e Na
Na+H2o NaOH+1/2 H2
☻NaOH we get it from sea water by precipitate the {calcium, magnesium}
By carbonate solution
Na2CO3 +CaAL2 ∆ CaCO3 +2 NaCL
Na2CO3 + MgCL2 ∆ MgCO3 +2NaCL
↓
{Precipitate}
☻ {CL2} and {H2} are by-product