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