20269.The mass of one Avogadro number of helium atom is
1.00 gram
4.00 gram
8.00 gram
4 x 6.02 x 1023 gram
20262.The main use of salt in the diet is to
make the taste of food better
produce in small amounts the hydrochloric acid required for the digestion of food
ease the process of cooking
increase the solubility of food particles in water
20293.The number of g-molecule of oxygen in 6.02 x 1024CO molecules is
1 gram of molecule
0.5 gram of molecule
5 gram of molecule
10 gram of molecule
20305.The number of waves made by an electron moving in an orbit having maximum magnetic quantum number is +3
4
5
2
zero
20285.The molecule which has the highest percentage of ionic character among the following is
HI
HF
HCI
HBr
20303.The isomerism which exists between CH3CHCI2 and CH2CI. CH2CI is
chain isomerism
functional group isomerism
positional isomerism
metamerism
20299.The organic reaction represented by equation CH3 - CH = O + H2NOH gives CH3 - CH - NH + H2O is an example of
an addition reaction
a condensation reaction
an oxidation reaction
an elimination reaction
20259.The inherited traits of an organism are controlled by
RNA molecules
nucleotides
DNA molecules
enzymes
20316.The names of the scientists, Newlands, Mendeleev, and Meyer are associated with the development of
atomic structure
metallurgy
periodic table of contents
discovery of elements
20271.The material which can be deformed permanently by heat and pressure is called a
thermoplastic
thermoset
chemical compound
polymer
20294.The most extensive, commercially useful source of thorium as monazite sand occurs in India at
Orissa coast
Travancore coast
West Bengal coast
Gujarat coast
20248.The gas present in the stratosphere which filters out some of the suns ultraviolet light and provides an effective shield against radiation damage to living things is
helium
ozone
oxygen
methane
20281.The following are the half lives of four active isotopes. Which one of the following is the most dangerous to handle?
3 billion years
100 years
0.01 minute
13 days
20304.The half life period of an isotope is 2 hours. After 6 hours what fraction of the initial quantity of the isotope will be left behind?
1/6
1/3
1/8
1/4