Question

Give scientific reasons.

(a) Buttermilk is churned to get butter .

(b) In chromatography, the ingredients of a mixture rise up to a limited height water rises up to upper end of the paper .

(c) A wet cloth is wrapped around a water storage container in summer .

Answer 1

a. Butter milk has two components- water and fat/cream. Churning helps in the separation of these two components. The fat/cream collects on the top as a result of churning while the remaining part is left behind as liquid.


b. Chromatography is a separation technique used to separate the different components in a liquid mixture. Separation of substances by chromatography is based on two properties of the substance:

• solubility of the substance in the solvent that moves up
• ability of the substance to stick to the stationary filter paper

These properties are different for different substances and are mutuall opposite to each other. It is the reason why all the components of the mixture rise upto a limited height when water rises up to the upper end of the paper.


c. A wet cloth is wrapped around water containers in summers to keep the container and the water inside it cools. The water present in the cloth evapourates and along with that water the heat also evapourates thus keeping the container and water cool.