Question

15 A child wanted to separate the mixtures of dyes constituting a sample of ink He
marked a line on the filter paper in a glass containing water.
a)What did the child observe?
b)Name the technique and write one precaution while doing the process​

Answer 1

Answer:

We have learnt that most of the natural substances are not chemically pure. Different methods of separation are used to get individual components from a mixture. Separation makes it possible to study and use the individual components of a mixture.

Heterogeneous mixtures can be separated into their respective constituents by simple physical methods like handpicking, sieving, filtration that we use in our day-to-day life. Sometimes special techniques have to be used for the separation of the components of a mixture.

How can we separate a solvent from its solute?

Activity 1 : How can we obtain coloured compound (dye) from blue/black ink?

Fill half a beaker with water.

Put a watch glass on the mouth of the beaker

Put few drops of ink on the watch glass.

Now start heating the beaker. We do not want to heat the ink directly. You will see that evaporation is taking place from the watch glass.

Continue heating as the evaporation goes on and stop heating when you do not see any further change on the watch glass.

Observe carefully and record your observations.

Fig.1

We find that ink is a mixture of a dye in water. Thus, we can separate the volatile component (solvent) from its non-volatile solute by the method of evaporation.

thanks for your I-9