QC Lab - Experiment 2: Preparation and Standardization of 1N Sodium Hydroxide Solution

standardization

Process of determining the exact concentration of a solution

Titration is one type of analytical procedure often used in this

titrant

solution with known volume and concentration

titrand/analyte

solution with known volume but unknown concentration

burette

-iron stand with burette clamp firmly attached (to stand)

- titrant placed inside

erlenmeyer/conical flask

- beneath burette

- standard solution: inside with primary/secondary standard + indicator

standard solution

primary/secondary standard + indicator

primary standard

–A standard that is sufficiently accurate that it cannot be calibrated or subordinate to other standards.

–

–Used to standardize secondary standards

–Used in titration to determine an unknown concentration and in other analytical chemistry techniques

- sodium carbonate, sodium tetraborate, potassium hydrogen phthalate/potassium diphthalate

6 properties of primary standard

1. high purity

2. stable

3. low hygroscopisity

4. high equivalent weight

5. non toxic

6. relatively cheap

low hygroscopisity

primary standard low tendency to absorb moisture from the air

secondary standard

–Chemical that has been standardized against a primary standard

sodium hydroxide

- lye (oldest name), caustic soda, soda lye

- crystalline odorless solid

- solid form = white

- liquid form = colorless

- deliquescent: absorbs moisture from air and dissolves into it

+ water = exothermic

- corrosive: solid/50% solution

–When dissolved in water or neutralized with acid, it liberates substantial heat which may be sufficient to ignite combustible materials.

–It is used in the manufacture of soaps, rayon, paper, explosives, dye stuff and petroleum products, etc.

lye, caustic soda, soda lye

sodium hydroxide other names

white

color of sodium hydroxide in solid form

colorless

color of sodium hydroxide in liquid form

deliquescence

absorbs moisture from air and dissolves into it (difference from hygroscopic)

corrosive

cause damage to living tissue = solid/50% solution

hard soap

sodium hydroxide soap

soft soap

potassium hydroxide soap

permanent

no longer colorless even with continuous swirling

pink coloration

faint pink (dark - too much = overtitrated pink)

titer

used to compute normality

total volume of liquid added from burette

normality

weight (PS)/molar mass (PS)/n (PS) x 1000/titer (mL)

IBR - FBR

acid

n = # of hydrogen ions

base

n = # of hydroxyl (OH) ions

salt

n = # of ionic charge