Real Lab Procedure
- Take a clean test tube from the test tube rack.
- Transfer some dal into this test tube using a spatula.
- Pour some distilled water into this test tube.
- Shake the solution properly to mix the compounds.
- Allow it to stand for 30 minutes.
- Draw out concentrated hydrochloric acid from its bottle using a dropper.
- Add a few drops of concentrated hydrochloric acid into the test solution.
Simulator Procedure (as performed through the Online Labs)
- You can select the food sample by clicking on the corresponding icon.
- Click and drag the distilled water bottle towards the test tube to add water to the test tube containing the food sample.
- Allow the test tube containing sample to stand till the needle of the clock stops moving.
- Click and drag the dropper towards the test tube to add conc.HCl to the test tube.
- Based on your observation, indicate the presence of Metanil yellow in the selected sample by clicking on the ‘Yes’ or 'No' radio button.
- You can redo the experiment by clicking on the ‘Reset’ button.
On adding conc. Hydrochloric acid to the sample, it turns pink in colour.
The pink colour indicates the presence of the adulterant Metanil yellow in the test sample.
Use conc. Hydrochloric acid judiciously.
Be careful while using concentrated Hydrochloric acid, as it is a strong acid.