151)Which one of the following is not an alloy?
brass steel
copper bronze
Answer :

152)Which one of the following can be used as insecticide?
DDT paracetamol
TNT gunpowder
Answer :

153)The ICs used in electronic devices are made up of
iron oxide silicon
chromium coal
Answer :

154)The difference between explosion and combustion is that
combustion is accompanid by loss of heat while an explosion is accompanied by absorption of heat combustion takes place only in air whele an explosion can occur even without air
combustion is a chemical reaction while an explosion is caused by physical factors there is rapid increase of pressure in confined spaces in case of an explosion, but no such change occurs during combustion
Answer :

155)In hospitals, the oxygen tubes for respiration contain oxygen and
helium nitrogen
argon carbon dioxide
Answer :

156)Acetyl salicyclic acid is commonly used as
a fertilizer a sedative
a pain killer tear gas
Answer :

157)The most commonly used substances in fluorescent tubes are
sodium vapour and neon sodium oxide and argon
mercuric oxide and neon mercury vapour and argon
Answer :

158)Aluminium in the earth's crust is found as
gypsum bauxite
cryolite native metal
Answer :

159)The commonly used medicine for typhoid is
ascorbic acid chloromycetin
chloroquin sulpha drugs
Answer :

160)Radiocarbon dating is used to estimate the ages of
rocks babies
fossils ancient buildings
Answer :

161)Ozone is important to mankind because it
creates a protective coverage against ultraviolet rays releases oxygen in the air
maintains the temperature of the earth absorb carbon dioxide
Answer :

162)The gas in the atmosphere that helps in burning is
hydrogen oxygen
nitrogen carbon dioxide
Answer :

163)Narmally the substances that fight against diseases in human are known as
enzymes deoxyribonucleic acids
carbohydrates antibodies
Answer :

164)During dehydration the substance that is usully lost by the body is
sodium chloride calcium phosphate
sugar potassium chloride
Answer :

165)Which one of the following is least prone to catch and spread fire?
terycot cotton
nylon polyester
Answer :

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