Question

Which of the following is not a property of mixture?
(a) does not have a sharp melting and boiling point
(b)heat is taken in or given out in the preparation
(c) can be separated by physical means
(d)may be homogenous or heterogenous

Answer 1

Hint: Mixtures are formed by the combination of different elements without any source of energy and have variable composition of constituents having different boiling and melting points and thus, are easy to separate. Now, identify the correct statement.

Complete step by step answer:
First of all, we should know what mixtures are. Mixtures are made up of two or more substances( i.e. consist of different types of elements). An element is that which consists of only one type of particle. These particles may be either atoms or molecules. E.g. sodium, copper, silver etc. all these contain atoms of one type only. In case of molecules two atoms combine to give their respective molecules. E.g. hydrogen, nitrogen and oxygen gases) combine i.e. get bonded together to form the compounds. water, ammonia, carbon dioxide etc. examples of mixtures are: sugar solution, dry air etc. These do not require any additional source of heat or release heat
In the mixtures, the substances are not bonded together and each of the substance present in it is having its own different properties and therefore, there ratio is not definite and thus, they have variable composition. So, its can be homogenous (if the components in the mixture are uniformly distributed) e.g. soil mixed with water or heterogeneous(if the components in the mixture are not uniformly distributed) e.g. air, water etc.
They can be easily separated by physical methods because in it each component has its own variable composition and different components have different melting and boiling points and their overall melting and boiling points are not very sharp. Physical methods like filtration, hand picking, distillation etc. can be used.

Hence, from the above given statements all are true except the option(b).

Note: In mixtures there is no chemical force between the constituent’s particles but in spite of this particles of the mixture remain together and they are different from the compounds which have definite and fixed composition.