3864.The couple between base units of DNA is through
Hydrogen bonding
Electrostatic bonding
Covalent bonding
vander Waal’s forces
3865.Sublimation is a process in which a solid
Changes into another allotropic form
Changes into liquid form
Changes into vapour form
None of the above
3866.Methanol and acetone can be separated by
Fractional distillation
Distillation
Steam distillation
Vacuum distillation
3867.Aniline is separated from a mixture by
Fractional crystallization
Fractional distillation
Vacuum distillation
Steam distillation
3868.Glycerol is purified by
Steam distillation
Vacuum distillation
Fractional distillation
Simple distillation
3869.Two immiscible liquids are separated by
Separating funnel
Fractional distillation
Chromatography
Sublimation
3870.Latest technique for purification, isolation and separation of organic compounds is-
Chromatography
Steam distillation
Crystallisation
Vacuum distillation
3871.Oils are purified by
Fractional distillation
Steam distillation
Vacuum distillation
Simple distillation
3872.Chromatography technique is used for the separation of
Small sample of mixture
Plant pigments
Dye stuffs
All
3873.A mixture of naphthalene and benzoic acid can be separated by
Chromatography
Sublimation
Fractional crystallization
Distillation
3874.A fractionating column is used in
Sublimation
distillation
fractional distillation
Chromatography
3876.The most satisfactory method for separating sugars is
Fractional distillation
Vacuum distillation
Chromatography
Steam distillation
3877.Azeotropic mixtures
Boil at different temperature
Are mixtures of solids
Are constant boiling mixtures
None of the above
3878.A mixture of camphor and benzoic acid can be easily separated by
Sublimation
Fractional distillation
Chemical method
Extraction -with solvents
3880.An organic compound A(C4H9Cl) on reaction with Na/diethyl ether gives a hydrocarbon which on monochlorination gives only one chloro derivative then, A is:
iso-butyl chloride
secondary butyl chloride
t-butyl chloride
n-butyl chloride
3881.Identify the wrong statement in the following
Atomic radius of the elements increases as one moves down the first group of the periodic table
Atomic radius of the elements decreases as one moves across from left to right in the 2nd period of the
Amongst isoelectronic species, smaller the positive charge on the cation, smaller is the ionic radius
Amongst isoelectronic species, greater the negative charge on the anion, larger is the ionic radius
3882.A catalyst is a substance which
increases the activation energy
increases the rate of reaction and increases the equilibrium concentration of products
changes the equilibrium of a reaction so that the concentration of the product increases
hastens the attainment of equilibrium
3883.Atomic number of an element gives
the number of nucleons in its atom
the number of electrons in its atom
the weight of the atom of the element
the total number of elementary particles in its atom