Preparation of (250 mL of 0.1M) Standard Solution of Oxalic Acid

Materials Required 

  • Weighing balance 
  • Watch glass 
  • Spatula  
  • Dropper  
  • 250cm3 measuring flask / Volumetric flask 
  • Wash bottle 
  • Oxalic acid 
  • Funnel 
  • Funnel stand 
  • Distilled water 

 

Procedure 

Real Lab Procedure

  • Obtain a dry watch glass and measure its empty weight. 
  • Determine the precise weight of a clean and dried watch glass. 
  • Place exactly 3.1500 g of oxalic acid on the watch glass and record this measurement in the laboratory notebook. 

Note: Always note weight up to the fourth decimal place and clean the balance before and after weighing the chemical. 

  • Gently transfer the oxalic acid from the watch glass to a clean and dry measuring flask using a funnel. 
  • Rinse the watch glass with distilled water, guiding any adhering particles into the flask with the aid of a wash bottle. 

Note: For this purpose, the volume of distilled water should not exceed 50 mL. 

  • Rinse the funnel multiple times with distilled water, directing the adhering particles into the measuring flask. Ensure minimal water usage, not exceeding 50 mL. 
  • Thoroughly rinse the funnel with distilled water, allowing the solution attached to the funnel to enter the measuring flask. 
  • Swirl the measuring flask until the oxalic acid completely dissolves. 
  • Carefully add sufficient distilled water in the measuring flask, ensuring it remains just below the etched mark. 
  • Use the last few millilitres of distilled water, drop by drop, until the reduced meniscus level touches the mark.  
  • Seal the flask with the stopper and gently shake to achieve a uniform solution. 
  • Calculate the solution as a Molar solution of oxalic acid at a 1/10 concentration (M/10). 

Simulator Procedure

  • Drag and drop watch glass onto the weighing machine to measure weight of the watch glass. 
  • Click on the bottle cap to open it. 
  • Drag and drop the spatula towards the bottle to take (3.1500)gm of oxalic acid. 
  • Drag and drop the spatula towards the watch glass to transfer oxalic acid to watch glass. 
  • Click on the Next button. 
  • Drag and drop the funnel to the top of the measuring flask. 
  • Drag and drop watch glass containing oxalic acid to the top of the funnel. 
  • Drag and drop the wash bottle to the top of the funnel to wash and pour any remains present inside the funnel. 
  • Drag the funnel outside the measuring flask and place it inside a stand. 
  • Drag and drop the measuring flask cap on top of it. 
  • Drag and drop the measuring flask on the canvas to shake it. 
  • Click on the cap of measuring flask to open. 
  • Drag and drop the funnel to the top of the measuring flask. 
  • Drag and drop the wash bottle to the top of the funnel to pour water into the measuring flask. 
  • Drag and drop the funnel to the stand. 
  • Drag and drop the dropper containing distilled water to the top of the measuring flask to pour the water up to the marking. 
  • Drag and drop the cap to close the measuring flask when the required quantity is present.there 
  • Drag and drop the measuring flask on the canvas to shake it. 
  • Click on the Inference button for the inference. 
  • Click the Reset button to redo the program. 

 

Calculation

  • M – Molarity of the solution 
  • V- Volume of the solution in cm3 
  • Mm – Molar mass of the solute 
  • Mass (m) of the solute expressed in grams = M×V×Mm/1000 
  • Hydrated oxalic acid = C2H2O4.2H2
  • Molecular mass of Oxalic Acid = 126. 
  • 12.6 g of oxalic acid per litre of the solution should be dissolved to prepare M/10 oxalic acid solution. 
  • Therefore, for preparing 250 mL of 0.1 M oxalic acid solution, we require  
  • 12.6 g× 250 mL/1000 mL =3.1500g of hydrated oxalic acid.   
  • Mass = 0.1 (mol)× 250(cm3) ×126 (g mol-1)/ 1000 (cm3
  • Mass = 3.1500g 

 

Observations

Weight of the watch glass W1g 
Weight of the watch glass + Oxalic acid W1 + 3.15g 
Weight of Oxalic acid 3.150g (Weight of watch glass – Weight of oxalic acid) 
Volume of distilled water 250cm

 

Result

250cm3 of decimolar or (M/10) solution of oxalic acid is prepared. 

 

Precautions

  • Handle chemicals carefully. 
  • Keep the weighing balance clean and neat. 
  • Handle glass apparatus carefully. 
  • Ensure the water level of the chemical balance is in the right position. 
  • Use lab coats, gloves and googles while handling the chemicals.