QC Lab - Assay of Sodium Chloride

NaCl

molecular formula of NaCl

58.44 g/mol

molecular weight of NaCl

appearance

±White crystalline solid

salt

table salt

rock salt

sea salt

halite

other names of sodium chloride

ionic compound

nacl representing a 1:1 ratio of sodium and chloride ions.

salt

nacl is the most responsible for the salinity of seawater and extracellular fluid of many multicellular organisms.

edible/table salt

form commonly used as a condiment and food preservative.

large quantities

±used in many industrial processes, and it is a major source of sodium and chlorine compounds used as feed stocks for further chemical synthesis.

second major application

±de-icing of roadways in sub-freezing weather.

generally recognized as safe

NaCl is a GRAS ingredient

procedure

±To perform this assay, weigh accurately about 0.25g of NaCl

±Dissolve in 50mL of water in a glass-stoppered flask

±Add 50mL of 0.1N silver nitrate, 3 mL of nitric acid, 5 mL of nitrobenzene and 2 mL of ferric ammonium sulfate TS

±Titrate with 0.1N ammonium thiocyanate solution

±Compute for percent purity.

99-100.5

USP-NF Requirement calculated on the dried basis. (same as zinc oxide)

nitric acid

prevent hydrolysis of indicator

agno3

used for formation of agcl ppt

nitrobenzene

added to aid the formation of agcl ppt while eliminating the need for further filtration

ferric ammonium sulfate

indicator = REDDISH-YELLOW ppt