Fractional distillation is suitable for separation of miscible liquids with a
boiling point difference of about 25 K or less. What part of fractional
distillation apparatus makes it efficient and possess an advantage over a
simple distillation process. Explain using a diagram.
Which of the following are not compounds?
(a) Chlorine gas
(b) Potassium chloride
(c) Iron
(d) Iron sulphide
(e) Aluminium
(f) Iodine
(g) Carbon
(h) Carbon monoxide
(i) Sulphur powder
Non metals are usually poor conductors of heat and electricity. They are
non-lustrous, non-sonorous, non-malleable and are coloured.
(a) Name a lustrous non-metal.
(b) Name a non-metal which exists as a liquid at room temperature.
(c) The allotropic form of a non-metal is a good conductor of electricity.
Name the allotrope.
(d) Name a non-metal which is known to form the largest number of
compounds.
(e) Name a non-metal other than carbon which shows allotropy.
(f) Name a non-metal which is required for combustion.
On heating calcium carbonate gets converted into calcium oxide and carbon
dioxide.
(a) Is this a physical or a chemical change?
(b) Can you prepare one acidic and one basic solution by using the
products formed in the above process? If so, write the chemical equation
involved.
Can we separate alcohol dissolved in water by using a separating funnel?
If yes, then describe the procedure. If not, explain.
Sucrose (sugar) crystals obtained from sugarcane and beetroot are mixed
together. Will it be a pure substance or a mixture? Give reasons for the
same.
Fill in the blanks
(a) A colloid is a ——— mixture and its components can be separated by
the technique known as ———.
(b) Ice, water and water vapour look different and display different ——
properties but they are ——— the same.
(c) A mixture of chloroform and water taken in a separating funnel is mixed
and left undisturbed for some time. The upper layer in the separating
funnel will be of——— and the lower layer will be that of ———.
(d) A mixture of two or more miscible liquids, for which the difference in
the boiling points is less than 25 K can be separated by the process
called———.
(e) When light is passed through water containing a few drops of milk, it
shows a bluish tinge. This is due to the ——— of light by milk and the
phenomenon is called ——— . This indicates that milk is a ———
solution.
Give an example each for the mixture having the following characteristics.
Suggest a suitable method to separate the components of these mixtures
(a) A volatile and a non-volatile component.
(b) Two volatile components with appreciable difference in boiling points.
(c) Two immiscible liquids.
(d) One of the components changes directly from solid to gaseous state.
(e) Two or more coloured constituents soluble in some solvent.