Harmful bacteria in drinking water cannot be destroyed by
chlorination
boiling
adding caustic soda
ozonisation
Correct Answer :
C. adding caustic soda
Related Questions
The depletion of the ozone layer in the upper atmosphere is due to -extensive use of
dichloro-phenoxy-acetic acid
superphosphate of lime
chlorofluorocarbons (CFC)
dichloro-diphenyl-trichloro-ethane
The atomic number of an element represents
number of neutrons in the nucleus
number of protons and neutrons in the nucleus
the valency of the element
number of protons in the nucleus
Which of the following statements regarding natural radioactivity is true?
It is spontaneous disintegration of atoms
It is induced by bombardment with projectiles
It is transmutation of atoms with projectiles
It is dependent on temperature
The principle involved in dialysis, a treatment administered to patients with affected kidneys is
Cataphoresis
Osmosis
Dehydration
Diffusion
The addition of a neutron to the nucleus of an atom
increases the atomic mass of the atom
decreases the atomic mass of the atom
increases the charge on the nucleus
decreases the charge on the nucleus
Which of the following is not a characteristic of potable water?
It must be free from suspended impurities
It must be free from harmful bacteria
It must contain traces of sodium bicarbonate
It must have a fishy odour
Consider the following statements: Hard water is not suitable for
1) drinking
2) washing clothes with soap
3) use in boilers
4) irrigating crops
Which of these statements are correct?
1 and 3
2 and 3
1, 2 and 4
1, 2, 3 and 4
Which one of the following is present in the largest amount in terms of per cent by mass in the earth's crust?
Silicon
Oxygen
Carbon
Calcium
Isotopes differ in the number of
Protons
Neutrons
Electrons
Protons and electrons
Rusting of iron cannot be prevented by
painting
applying alkaline phosphate
applying soap water
galvanising
The presence of dust particles in air serves
as a nucleus to condense water vapour resulting in rain
to maintain the average density of air
to minimise the inflammatory nature of oxygen
to protect the inhabitants of the earth from the effects of ultra violet rays.
The simplest hydrocarbon is
benzene
methane
ethane
butane
The pure at form of iron is
wrought iron
steel
pig iron
nickel steel
Gases have
a definite shape but not volume
a definite volume and shape
a definite volume but not shape
neither definite volume nor shape
Biogas is obtained during
decomposition of petrol
fermentation of animal and plant waste
destructive distillation of coal
electrolysis of water
Which of the following represents a physical change?
sublimation
oxidation
reduction
decomposition
Laughing gas is
nitric oxide
nitrogen peroxide
nitrogen pentoxide
nitrous oxide
When ants bite, they inject
glacial acetic acid
methanol
formic acid
stearic acid
One of the ingredients of the paste on the side of a match box is
phosphorus pentaoxide
phosphorus trichloride
phosphorus trisulphide
phosphorus trioxide
Penicillin was discovered by
Alexander Fleming
Sir JJ Thomson
Dr Nessler
Sir John Russel
The raw materials required for the manufacture of glass are
silica, sodium nitrate and soda ash
silica, limestone and sodium nitrate
silica, sodium oxide and limestone
silica, soda ash and limestone
Vinegar is the trade name for
chloroform
acetic acid
phenol
carbon tetrachloride
The term 'nucleons' apples to
neutrons
protons
protons and neutrons
protons and electrons
The science which deals with the chemistry of life processes is known as
electrochemistry
physical chemistry
biochemistry
tinctorial chemistry
Dust particles in the air of large industrial cities are removed by
Sedimentation
Electrophoresis
Tyndall effect
Brownian movement
Petroleum ether is also known as
kerosene
naphtha
lubricating oil
asphalt
Rusting is a special case of corrosion applied to
nickel
tin
iron
chromium
The vitamin that is found in citrus fruits such as lemon and orange is
vitamin C
vitamin B2
vitamin A
vitamin E
Optical instruments are made of
pyrex glass
flint glass
quartz glass
Crooke's glass
What is 'oxygen mixture'?
A mixture of potassium nitrate and carbon
A mixture of ammonium chloride and sodium nitrate
A mixture of potassium chlorate and manganese dioxide
A mixture of ammonium nitrate and charcoal