Q1. Which one of the following has the highest fuel value?(1997)
(a) Hydrogen
(c) Natural Gas
(b) Charcoal
(d) Gasoline
Ans. (a)
Exp. Among the given fuels, hydrogen has the highest fuel value, i.e. 150 kj/g. Fuel value for other fuels are as follows:
Fuels Fuel values (kj/g)
(1) Natural gas 55
(2) Gasoline 43
(3) Charcoal 33
The fuel value or calorific value is defined as the amount of heat produced in calories or joules when one gram of a substance (fuel) undergoes complete combustion
Q2. Which one of the following is used as an antifreeze for the automobile engines? (1997)
(a) Propyl alcohol
(c) Methanol
(b) Ethanol
(d) Ethylene glycol
Ans. (d)
Exp. Among the given compounds, ethylene glycol (IUPAC name: ethane 1, 2 diol) having chemical formula HOCH₂CH₂OH is used as an anti-freeze for the automobile engine. It is used in automobile engines to remove waste heat. Pure ethylene glycol freezes at about -12°C but when mixed with water, the mixture does not readily crystallise and therefore, the freezing point of the mixture is depressed is used to achieve freezing point for cold environment
Q3. Which one of the following sets of elements was primarily responsible for the origin of life on the Earth? (2012)
(a) Hydrogen, oxygen, sodium (b) Carbon, hydrogen, nitrogen
(c) Oxygen, calcium, phosphorus
(d) Carbon, hydrogen, potassium
Ans. (b)
- Exp. Carbon, hydrogen and nitrogen is the set of elements was primarily responsible for the origin of life on the earth. Origin of life started with the formation of simple organic molecules like nucleoside.
- The building blocks of nucleoside are carbon, hydrogen. oxygen, nitrogen and phosphorus.
- Carbon is the most important of these because of its capability to form a wide variety of compounds
Q4. The increasing amount of carbon dioxide in the air is slowly raising the temperature of the atmosphere, because it absorbs (2012)
(a) the water vapour of the air and retains its heat
(b) the ultraviolet part of the solar radiation
(c) all the solar radiations
(d) the infrared part of the solar radiation
Ans. (d)
Ent. The increasing amount of carbon dioxide in the air is slowly raising the temperature of the atmosphere, because it absorbs the infrared part of the solar radiation.
Sun emits many kinds of radiations (collectively called solar radiations) like UV rays, visible light rays, infrared rays, etc.
Any solar radiations can produce heat (including visible and ultraviolet) but the infrared portion is the one that produces most heat and it is the one which is actually absorbed by the carbon dioxide in the atmosphere.
Q5. Consider the following statements.
If there were no phenomenon of capillarity
(2012)
- it would be difficult to use a kerosene lamp.
- one would not be able to use a straw to consume a soft drink.
- the blotting paper would fail to function.
- the big trees that we see around would not have grown on the Earth.
Which of the statement(s) given above are correct?
(a) 1,2 and 3
(b) 1,3 and 4
(c) 2 and 4 (d)All of thesAns.(b)
Exp. Statements (1), (3) and (4) are correct. Capillary action or capillarity is the ability of a liquid to flow in narrow spaces without the assistance of, and in opposition to external forces like gravity.
The effect can be seen in the drawing up of liquids between the hairs of a paint-brush, in a thin tube, in porous materials such as paper, in some non-porous materials such as
Q6. Consider the following pairs. (2017)
Commonly used/consumed materials Unwanted or controversial chemicals likely to be found in them 1.lipstick Lead 2.Soft drinks Brominated vegetable oils
3.Chinese fast food Monosodium glutamate
Which of the pairs given above is/are correctly matched?
(a) Only 1
(b) 2 and 3
(c) 1 and 3 (d) All of these
Ans. (d)
Exp. All the given pairs are correctly matched Lead is present in the several lipsticks in dangerous level that can be detected with a gold ring. Brominated Vegetable Oil (BVO) is a complex mixture of plant-derived triglycerides that have been reacted to contain atoms of the element bromine bonded to the molecules. Brominated vegetable oil is used primarily to help emulsify citrus-flavoured soft drinks. A food additive called Monosodium Glutamate (MSG), which is a flavour enhancer, is often blamed for the symptoms some people experience after eating Chinese food.
Q7. Steel slag can be the material for which of the following? (2020)
- Construction of base road
- Improvement of agricultural soil
- Production of cement
Select the correct answer using the code given below.
(c) 1 and 3
(b) 2 and 3
(a) 1 and 2
(d) 1,2 and 3
Ans. (d)
Exp. All statements (1), (2) and (3) are correct. Steel slag can be the material for construction of as road, improvement of agricultural soil and production of cement. Steel slag is by-product of steel making. It is produced during the separation of the molten steel from impurities in steel-making furnaces. Slag is very hard and resistant to both weather and wear. It is widely used in road construction. Application of slag in soil favors the increase of pH and the availability of nutrients such as Ca, Mg, and Si in the soil, which leads to the increase in the absorption of these elements by the plant, favoring the growth and yield of the crops. Steel-slag can be used to produce energy-saving cement by co-grinding with OPC clinker and blast furnace slag. It can replace Portland cement in various applications and is especially suitable for projects where a low heat of hydration is required
‘Q8. Triclosan’, considered harmful when exposed to high Beer levels for a long time, is most likely present in which of the following? (2021)
(a) Food preservatives
(b) Fruit-ripening substances
(c) Re-used plastic containers (d) Toiletries
Ans. (d)
Exp. “Triclosan’ is present in toiletries to reduce bacterial contamination. Triclosan is an ingredient added to many consumer products intended to reduce or prevent, bacterial contamination. It is added to soaps and body washes, tooth pastes and some cosmetics. Other options like food preservative contains sodium benzoate. Acetylene is ethylene is used as fruit ripening substance.
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