In the purification of an impure organic compound by recrystallization, 2.292g of a pure compound was obtained from a 2.500g impure sample. Calculate the % of the pure component of the compound.

Mass of pure compound $= 2.292 \text{ g}$
Mass of impure sample $= 2.500 \text{ g}$

The correct option is C.

10. During a hearing in a court case, the judge suspected that some changes in the document had been carried out. He asked the forensic department to check the ink used at two different places. Which technique do you suggest can give the best results?
D. Thin Layer Chromatography
Thin Layer Chromatography (TLC) is an effective technique for separating and identifying the components of a mixture, such as ink. By comparing the chromatograms of ink samples from different parts of the document, forensic scientists can determine if the same ink was used or if alterations were made.

11. Chemical waste should be disposed off by _____
B. putting it into a hazardous waste container.
Proper disposal of chemical waste is crucial for safety and environmental protection. Hazardous chemical waste must be collected in designated containers and handled according to specific safety protocols, not poured down drains or put in regular trash.

12. Some toxic chemicals _____
D. All of the above
Toxic chemicals can enter the body through various routes:
A. They can be assimilated directly through the skin (absorption) if proper protection is not used.
B. They can be inhaled, even if they have a high boiling point, as some may still have significant vapor pressure or form aerosols.
C. They can be ingested by transferring from hand to mouth, especially after leaving the laboratory without proper handwashing.
Therefore, all the listed options are correct ways toxic chemicals can enter the body.