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

# Materials Required

Weighing balance, Watch glass, Weight box, 250ml beaker, Glass rod, 250cm3 measuring flask / Volumetric flask, Wash bottle, Weighing tube, Oxalic acid, Funnel, Funnel stand, Distilled water

# The Procedure

## Calculation

• Mass (m) of the solute expressed in grams = MVMm/1000
• M – Molarity of the solution
• V- Volume of the solution in cm3
• Mm – Molar mass of the solute
• Hydrated oxalic acid = C2H2O4.2H2O
• 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.
• Mass = 0.1 (mol)* 250(cm3) *126 (g mol-1)/ 1000 (cm3)
• Mass = 3.1500g

## Real Lab Procedure

• Take a dry watch glass and take the empty weight of the watch glass
• Weigh the exact amount of clean and dried watch glass.
• Weigh correctly on the watch glass 3.1500 g of oxalic acid and record this weight in the notebook.

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

• Using a funnel, transfer oxalic acid softly and carefully from the watch glass into a clean and dry measuring flask.
• Wash the watch glass with distilled water to move the particles that stick to it into the foam with the assistance of a wash bottle.

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

• Wash funnels several times with distilled water to move the sticking particles into the measuring flask using a wash bottle. Add water in tiny quantities while washing the funnel. The distilled water quantity used for this purpose should not exceed 50 mL.
• Using a wash bottle, wash the funnel carefully with distilled water to pass the solution attached to the funnel into the measuring flask
• Turn the flask of measurement until the oxalic acid dissolves.
• Using a wash bottle, thoroughly add enough distilled water to the measuring flask just below the etched mark on it.
• Add the last few mL of distilled water drop into the measuring flask until the reduced meniscus level just touches the mark.
• Put the stopper on the mouth of the flask and shake softly to make the entire solution uniform. Calculate it as a solution of oxalic acid 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.
• Drag and drop the watch glass towards the funnel placed at the top of the measuring flask
• 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 on the canvas to shake it
• Drag and drop the dropper to the beaker collect some water from beaker
• Drag and drop the dropper containing distilled water to the top of the measuring flask to pour the water inside it.
• Drag and drop the stopper to close the measuring flask when the required quantity is there
• Drag and drop the measuring flask on the canvas to shake it.
• Click the reset button to redo the program

# 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 250cm3

# 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.