Quiz on Assay of Sodium Chloride

What is the first step in the Volhard method for the assay of sodium chloride?

• Add 25 mL of 0.1 N Silver nitrate

• Weigh accurately about 125 mg of sodium chloride

• Titrate the excess Silver nitrate

• Dissolve the sodium chloride in 25 mL of water

What is the purpose of adding nitric acid in the procedure?

• To dissolve the sodium chloride

• To precipitate silver chloride

• To stabilize the solution

• To enhance the color change

According to USP specifications, what is the acceptable percentage range of sodium chloride?

• 95.0% to 97.0%

• 100.0% to 101.0%

• 99.0% to 100.5%

• 98.0% to 99.5%

What is used to titrate the excess Silver nitrate?

• 0.1 N Sodium hydroxide

• 0.1 N Potassium permanganate

• 0.1 N Hydrochloric acid

• 0.1 N Ammonium thiocyanate

What is the reaction that occurs when sodium chloride reacts with silver nitrate?

• NaCl + KCl → KNa + Cl2

• NaCl + NaOH → Na2O + HCl

• NaCl + AgNO3 → AgCl + NaNO3

• NaCl + H2O → NaOH + HCl

What is the role of ammonium thiocyanate in the Volhard method?

• To precipitate silver chloride

• To enhance the color change during titration

• To react with excess silver nitrate

• To stabilize the sodium chloride solution

What is the significance of the endpoint in the titration process?

• It indicates the complete reaction of sodium chloride

• It shows the presence of excess silver nitrate

• It determines the concentration of sodium chloride

• It marks the formation of silver chloride

Which indicator is commonly used in the Volhard method?

• Phenolphthalein

• Methyl orange

• Ferroin

• Starch

What is the purpose of using ammonium thiocyanate in the titration process?

• To enhance the stability of the solution

• To react with silver ions

• To precipitate silver thiocyanate

• To provide a color change indicator

Which compound is formed when sodium chloride reacts with silver nitrate?

• Silver chloride

• Sodium nitrate

• Both silver chloride and sodium nitrate

• None of the above