Mixture of sulphur and sand can be separated through solvent extraction method.  

Curdling is the breaking of an emulsion or colloid into large parts of different composition through the physico-chemical processes of flocculation, creaming and coalescence.

After harvesting, wheat or paddy stalks are dried in the sun and grains can be separated from the stalks by threshing. 

Clear solution, filtrate and pure substances are all pure, but impurities are the substances which make things impure. 

Evaporation refers to the conversion of a liquid to its vapour state. During evaporation, water changes from liquid to gas.

Winnowing is a method by which particles of the same size can be separated easily. 

Components are the substances which make a mixture. Pulses can be separated from salt by sedimentation as pulses settle down at the bottom. Sand can be separated from stones by sieving. Butter can be separated from curd by churning and not decantation. 

Chalk powder is insoluble in water. Out of salt, sugar and baking powder, salt particles are the smallest in size and thus, get dissolved the fastest in water. 

The mixture can be separated on the same principle as sedimentation and decantation.

The process of conversion of water vapour into its liquid form is called condensation. When the boiling water evaporated, it encountered the plate that was being used as a cover. The water vapour turned back into water upon encountering the cooler plate. This is called condensation.

For 1 - Method of handpicking is used. For 2 - Method of winnowing is used. For 3 - The method used is sieving. For 4 - The method used is filtration.

The component which can be blown away by the wind has to be lighter. Out of grains, sand, stone and sawdust, only sawdust is the impurity which is lighter in weight and can easily be blown off by wind. 

The mud in muddy water is heavier and settles down when this water is kept undisturbed for some time. The process is known as sedimentation. After this, the lighter impurities can be separated by the process of filtration. So, sedimentation followed by filtration can be used to purify muddy water. 

Mixture of alcohol + water and blood are homogeneous mixtures, i.e. the mixtures which have uniform composition and properties throughout. Sand is an example of a heterogeneous mixture. A heterogeneous mixture is made of different substances that remain physically separate. Heterogeneous mixtures always have more than one phase.

Statements a and b are correct.