science
Brass gets discoloured in air because of the presence of which of the following gases in air?
Hydrogen sulphide
Chemical formula for water is
H2O
The average salinity of sea water is
3.5%
What is laughing gas?
Nitrous Oxide
Water is a good solvent of ionic salts because
it has a high dipole moment
Which of the following is a non metal that remains liquid at room temperature?
Bromine
The gas usually filled in the electric bulb is
nitrogen
Heavy water is
deuterium oxide
Actinides are the elements with atomic numbers from
89 to 103
What is the lightest metal?
Lithium
Chlorophyll is a naturally occurring chelate compound in which central metal is
magnesium
Which of the gas is not known as green house gas?
Hydrogen
The element common to all acids is
hydrogen
The two elements that are frequently used for making transistors are
silicon and germanium
The main constituents of pearls are
calcium carbonate and magnesium carbonate
Which of the following metals forms an amalgam with other metals?
Mercury
The gases used in different types of welding would include
oxygen and acetylene
Monazite is an ore of
thorium
The filament of an electric bulb is made of
tungsten
Which of the following metals remain in liquid for under normal conditions?
Mercury
Bromine is a
red liquid
The hardest substance available on earth is
Diamond
Soda water contains
carbon dioxide
Diamond is an allotropic form of
carbon
Balloons are filled with
helium