pag 2 - acid base titration

Question 1

What is the method for making 1 moldm-3 of standard solution of NaHCO3

Answer 1

• weigh 2.1g of sodium hydrogencarbonate into a wweighing boat tranfer to a 250 cm3 beaker
• add a samll volume of distilled water to a beaker and strid until solid completley dissolves
• tranfer olution to 250 cm3 volumetric flask using a funnel
• rinse beaker and glass rod with ditilled water add washing to volumetric flask
• fills volumetric flask till graduated line using distilled water
• stopper the flask and invert few time to mix solution

Question 2

Describe how you would find conc HCL using tirtration with NaHCO3

Answer 2

• ue pipette transfer 25cm3 of standard NaHCO3 solution to 250cm3 conical flask
• add two to three drops of methyl orange
• fill burette with HCL to ensure no air bublle record intital burette reading
• add HCL from burette to conical flask until end point is reached and acid dropwise near end point solution change from yellow to orange
• record final burette reading calculate difference between initial and final burette reading
• repeat till two concordant results

Question 3

What is the calculation for the titration of HCL to NaHCO3

Answer 3

• caclulate mean titre using concordant results
• calculate moles NaHCO3 in 25cm3
• calculate mole HCL
• calculate concentration HCL

Question 4

What are the errors that can occur while making the standard solution and the titration

Answer 4

• some weighed NaHCO3 transferred weighing boat - use weiging different technique
• take care not to spill any solid or solution during transfer
• forcing all liquid from pipette - pipette i calibrated account liquid remain in tip
• during titration swrirl while adding acid ensure reactants are well mixed
• colour change no visible place white tile under conical flask

Question 5

What are the safety measures in the acid base titration

Answer 5

• HCL-severe skin burns and eye damage
• methyl orange - toxic if swallowed