111. Which of the following is a characteristic of an exothermic reaction?

1. Release of heat
2. Absorption of heat
3. Doesn’t involve any change in temperature
4. None of the option is correct

Option “A” is correct
An exothermic reaction is a chemical reaction that releases energy by light or heat.
112. __________ acts as a shield absorbing ultraviolet radiation from the sun.

1. Troposphere
2. Stratosphere
3. Mesosphere
4. Ionosphere

Option “B” is correct
The stratosphere is the second major layer of Earth’s atmosphere, just above the troposphere, and below the mesosphere. Ozone in the stratosphere absorb ultraviolet light from the Sun, providing a shield that prevents this radiation from passing to the Earth’s surface.
113. Iodised salt is beneficial for –

1. Lowering of blood pressure
2. Prevention of dehydration
3. Thyroid function
4. Salivary glands

Option “C” is correct
Iodised salt is beneficial for thyroid function because iodine is required for the synthesis of a hormone called thyroxine.
114. Submarines move under water. They have engines that run on –

1. Solar energy
2. Diesel
3. Batteries
4. Steam

Option “B” is correct
Most submarines except nuclear ones have diesel-electric engines.
115. The residue left after extracting juice from sugar beet and sugarcane is called –

1. Molasses
2. Bagasse
3. Whey
4. Biomass

Option “B” is correct
Bagasse is the fibrous matter that remains after sugarcane or sugarbeet stalks are crushed to extract their juice.
116. Gasohol is a mixture of:

1. Gasoline and Butanol
2. Gasoline and Ethanol
3. Gasoline and Propanol
4. Methanol and Ethanol

Option “B” is correct
Gasohol, a gasoline extender made from a mixture of gasoline (90%) and ethanol (10% often obtained by fermenting agricultural crops) or gasoline (97%) and methanol or wood alcohol (3%). Gasohol has higher octane or antiknock properties by which it burns more slowly, coolly and completely.
117. The plants receive Nitrogen in form of:

1. Nitric oxide
2. Nitrate
3. Ammonia
4. Nitride

Option “B” is correct
Ammonium (NH4+) and nitrate (NO3–) are the predominant inorganic forms of nitrogen in the soil. Plants normally use nitrogen in the form of nitrate.
118. To avoid ‘knocking’ of the engine of a car, which one of the following is used as an anti-knocking agent?

1. Ethyl alcohol
2. Butane
3. Tetra Ethyl Lead
4. White Petrol

Option “C” is correct
Tetraethyl Lead (CH3CH2)4Pb is the chief antiknock agent for automotive gasoline or petrol.
119. ________ is made by mixing iron with carbon and metals like chromium, nickel and manganese.

1. Ship
2. Stainless Steel
3. Rust
4. Ozone

Option “B” is correct
Stainless Steel is made by mixing iron with carbon and metals like chromium, nickel and manganese.
120. The salt concentration (measured as salinity in parts per thousand), is _______% in sea.

1. 10-20
2. 30-35
3. 40-50
4. 60-70

Option “B” is correct
Seawater in the world’s oceans has a salinity of approximately 3.5% or 35 parts per thousand.