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- Quiz (1): Second year student, Chemistry-Physics group
- Twenty-five milliliters of a 0.1123 M solution of HCl are diluted in a 100.0 mL volumetric flask. A solution containing sodium hydroxide (MW=40.00 g/mol) requires 25.76 mL of the dilute HCl for neutralization. How many milligrams of NaOH are in the sodium hydroxide solution?
(5)
- You are required to manufacture a 5.0 ppm (w/v) solution of NaOH. How much NaOH (mg) must be placed in a 100.0 mL volumetric flask to make this solution?
(3)
- What volume of 0.01227 M HCl would be required to titrate 25.00 mL of the solution manufactured in the previous question?
(5)
- What Na2CO3 mass (MW=105.9 g/mole) is required to neutralize 22.31 mL of 0.1017 M HCl? What type of indicator would you use for this titration? Why?
(7)
- 5.3573 grams of Na2CO3 (MW=105.9 g/mole) are placed in a 1.0 L volumetric flask. A 25.00 mL aliquot of this solution is neutralized with 11.55 mL of HCl. What is the molarity of the HCl solution?
(5)
- A 0.3731 g mass of EDTA (MW = 372.240 g/mol) is made up to volume in a 100.0 mL volumetric flask. Calculate MEDTA through molecular weight.
(2)
- A solution of sodium thiosulfate was standardized using 0.2210 g of potassium iodate (MW = 214.00 g/mol) in water with excess KI and HCl for acidification. The liberated I2 was titrated with 41.64 mL of sodium thiosulfate.
- Show the reaction equations involving iodine liberation and subsequent thiosulfate titration.
(4)
- Calculate Mthio.
(5)
- A mass of 2.210 g KBrO3 (MW = 167.001 g/mol) is placed in a 250.0 mL volumetric flask. A 10.00 mL aliquot is removed and placed in 100 mL of water containing excess KI and acid. The liberated iodine requires 23.32 mL of thiosulfate for complete reaction.
- Calculate Mthio.
(6)
- What indicator is used for this titration? Describe the indicator colour before titration point is reached and why (how) this colour is generated.
(3)
- Why is important to add the indicator just before reaction is complete?
(1)