Heena Sharma, Shubhankat Vats and, Rashmi Gupta Solutions for Chapter: Is Matter Around Us Pure?, Exercise 7: Challengers*

Two chemical species $\mathrm{X}$ and $\mathrm{Y}\mathrm{}$combine together to form a product $\mathrm{P}$ which contains both $\mathrm{X}$ and $\mathrm{Y}$, $\mathrm{X}\mathrm{}+\mathrm{}\mathrm{Y}\to \mathrm{P},\mathrm{}\mathrm{X}$ and $\mathrm{Y}$ cannot be broken down into simpler substances by simple chemical reactions. Which of the following concerning the species $\mathrm{X},\mathrm{}\mathrm{Y}$ and $\mathrm{P}$ are correct?

(i) P is a compound

(ii) X and Y are compounds

(iii) X and Y are elements

(iv) P has a fixed composition

The purpose of separating the components of a mixture is

Which flow chart correctly describes a homogenous material?

Tyndall's effect can be observed in a colloidal solution. Consider light scattering in the following:
I. When sunlight passes through the canopy of a dense forest.
II. When normal light passes through copper sulphate solution.
III. When normal light passes through milk.
IV. When a fine beam of light enters a room through a small hole.
Tyndall's effect is observed in

A colloid consists of the dispersed phase and dispersed medium. Aerosol is one type of colloid. Aerosol is made up of which of the following combination?
I. Gas in liquid
II.Liquid in gas
III. Solid in gas
IV.Gas in solid

Among the following statement, point out the incorrect separation technique.
I.Separation of colloidal particles from solution- centrifugation.
II.Separation of two miscible liquids- separating funnel.
III.Separation of pure substance from its impure form- crystallisation.
IV.Separation of components with the help of the same solvent- chromatography.

Which of the following are chemical changes?
I. Decaying of wood.
II. Burning of wood.
III. Sawing of wood.
IV. Hammering of a nail into a piece of wood.

White gold used in jewellery contains two elements, gold and palladium. A jeweller has two different samples that are both identical in appearance and have a uniform composition throughout. What can be said about the samples?